*Review* **A Review of Urban Ecosystem Services Research in Southeast Asia**

**Karen T. Lourdes <sup>1</sup> , Chris N. Gibbins <sup>2</sup> , Perrine Hamel 3,4 , Ruzana Sanusi 5,6, Badrul Azhar <sup>5</sup> and Alex M. Lechner 1,7,\***


**Abstract:** Urban blue-green spaces hold immense potential for supporting the sustainability and liveability of cities through the provision of urban ecosystem services (UES). However, research on UES in the Global South has not been reviewed as systematically as in the Global North. In Southeast Asia, the nature and extent of the biases, imbalances and gaps in UES research are unclear. We address this issue by conducting a systematic review of UES research in Southeast Asia over the last twenty years. Our findings draw attention to the unequal distribution of UES research within the region, and highlight common services, scales and features studied, as well as methods undertaken in UES research. We found that while studies tend to assess regulating and cultural UES at a landscape scale, few studies examined interactions between services by assessing synergies and tradeoffs. Moreover, the bias in research towards megacities in the region may overlook less-developed nations, rural areas, and peri-urban regions and their unique perspectives and preferences towards UES management. We discuss the challenges and considerations for integrating and conducting research on UES in Southeast Asia based on its unique and diverse socio-cultural characteristics. We conclude our review by highlighting aspects of UES research that need more attention in order to support land use planning and decision-making in Southeast Asia.

**Keywords:** natural capital; blue-green infrastructure; urban environmental challenges; Global South; tropical cities

#### **1. Introduction**

The global urban population has grown rapidly in the last few decades, with over 70% of the population in the Global North now residing in urban areas [1]. Similar trends are evident in the Global South and while developed regions may be better equipped to manage urban transformations [2], cities in developing regions such as Southeast Asia face increasing environmental pressures. In 2018, an estimated 320 million people lived in the urban areas of Southeast Asia (49% of the region's total population), and this figure is expected to increase to 66% of the total population by 2050 [1,3]. This rapid urbanisation has been accompanied by a range of environmental problems, including

**Citation:** Lourdes, K.T.; Gibbins, C.N.; Hamel, P.; Sanusi, R.; Azhar, B.; Lechner, A.M. A Review of Urban Ecosystem Services Research in Southeast Asia. *Land* **2021**, *10*, 40. https://doi.org/10.3390/land10010040

Received: 10 December 2020 Accepted: 28 December 2020 Published: 5 January 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

the urban heat island effect, floods, poor air quality and noise pollution, all of which directly impact the health of urban residents [4–11]. These issues are expected to be further exacerbated by the general vulnerability of the region to climate change impacts [12–14]. Moreover, countries within Southeast Asia have extremely diverse biophysical, cultural, socio-economic and political characteristics (Table 1). Levels of urbanisation range from 23% (Cambodia) to 100% (Singapore) and gross national incomes range from the 11th (Singapore) to the 162nd (Myanmar) rank globally. Efforts to mitigate urban environmental challenges should take into consideration these characteristics, in so doing provide contextspecific solutions [15–17].

*Land* **2021**, *10*, 40



Planning and designing cities to incorporate blue-green spaces is vital for mitigating socio-environmental problems affecting health and well-being [23–25]. Urban blue-green spaces promote greater resilience, sustainability and liveability in cities through the provision of services such as shading and cooling, carbon sequestration, stormwater management, noise attenuation, habitat for biodiversity and recreational opportunities [26–30]. These services, termed 'urban ecosystem services' (UES), capture the role of water (blue) (i.e., lakes and wetlands) and vegetation (green) (i.e., parks and urban forests) in or near the built environment at different spatial scales (streets, buildings, cities, regions) [31–33]. Generated through the functions and processes of blue-green structures, UES can alleviate the environmental pressures of urbanisation and enhance the wellbeing of urban residents [34–39].

The complex pathways through which UES are delivered can be analysed by the relationships between (i) structures (e.g., mangrove forests), (ii) their biophysical processes and functions (e.g., wave attenuation), and (iii) the derived services that deliver goods and benefits to humans (e.g., coastal flood protection) [40]. The interactions between these different components can be illustrated through frameworks such as the cascade model, which acts as a communication tool between experts and local stakeholders to help support UES assessments for urban planning [41]. Moreover, incorporating UES into urban planning requires an understanding of the various interactions between services, which are linked to one another as they stem from the same structures and functions of a particular ecosystem [42,43]. These interactions include synergies and tradeoffs, described respectively as positive-positive or positive-negative relationships between two or more services [44,45].

Research on UES can also be undertaken from various perspectives, given the interdisciplinary nature of the concept. The field has gained prominence for its ability to integrate natural and social sciences, communicating the dependence of society on ecological structures [43]. A wide range of methods have been used to characterise UES and assess their value to humans. These methods range from biophysical modelling to social surveys applied at various scales (e.g., landscape scale, site-based scale), with benefits valued biophysically (e.g., tonnes of carbon sequestered per year), economically (e.g., \$500 per hectare per year) and socio-culturally (e.g., sense of place) [46–48]. UES hold diverse values to various communities and the valuation of UES is necessary to understand local demands or benefits [30,49]. Valuations should be supported by the involvement of stakeholders to further deepen the understanding of local UES needs, while promoting the consideration of alternative management options [50,51].

Previous reviews of global UES research by Haase [28] and Luederitz [41] highlight that research has mostly been undertaken in Europe and North America, with research in Asia dominated by China. Although these reviews have explored the scope and nature of research on a global scale, they lack the finer resolution needed to understand patterns and traits of research in any one region. Despite the rapid economic growth and urbanisation in Southeast Asian countries, UES research across this region has not been reviewed. Hence, a systematic review of UES is timely, to assess the nature and extent of research on UES in Southeast Asia.

This review covers the last 20 years, the period within which the global UES literature has burgeoned. Inspired by Luederitz [41], we address four specific research questions: (1) How is UES research distributed across Southeast Asia and at what scale(s) are UES analysed? (2) Does UES research focus on single or multiple services and what type of blue-green structure are assessed? (3) Which components of the 'cascade' are assessed, and how are the interactions between UES conceptualised and stakeholders involved? (4) What research perspectives, and data collection and analytical methods are used to assess UES? Upon reviewing the current state of research in the region, we discuss the challenges and considerations for integrating UES research given the unique context of Southeast Asia. We conclude our review with recommendations for UES research in order to support planning in the region.

#### **2. Methods**

The search string composed terms that expressed the geographical area of interest ('Southeast Asia' and all the countries within the region), the topic of interest ('ecosystem service', its alternative term 'natural capital' and, to capture studies that did not explicitly refer to these two phrases, we included the keywords 'human', 'environment' and 'benefit') as well as terms that further specified the subtopic of interest (i.e., the urban environment). The search was applied to publication Titles, Abstracts and Keywords in the Scopus and Web of Science database as shown below:

(TITLE-ABS-KEY (("Southeast Asia" OR "South East Asia" OR "Indonesia" OR "Vietnam" OR "Thailand" OR "Malaysia" OR "Singapore" OR "Philippines" OR "Cambodia" OR "Laos" OR "Myanmar" OR "Brunei" OR "Timor-Leste"))) AND (TITLE-ABS-KEY (("ecosystem service\*" OR "natural capital" OR ("human" AND "environment" AND "benefit\*")))) AND (TITLE-ABS-KEY ("urban" OR "city" OR "cities"))

The initial search return was refined to include only journal articles, book chapters and conference papers (see Supplementary Material for complete search string). This search returned a total of 255 unique articles published in the English language. The abstracts of the returned articles were screened manually to include publications within the scope of this review based on the following guiding criteria:


The final list comprised 149 empirical articles, assessing one or more ecosystem services in urban Southeast Asia (see Table S1 in Supplementary Material). Studies that investigated multiple urban areas within and outside of Southeast Asia were included in the review, if at least one study site was located within Southeast Asia. Each article was classified to identify information relevant to the four research questions, as described in the sections which follow. Refer to Table S2 in Supplementary Material for further details on definitions and classification protocol.

(1) How is UES research distributed across Southeast Asia and at what scale(s) have they been analysed?

Following the TEEB classification for ecosystem services [52], we classified the ecosystem services studied into four main categories: (i) provisioning, (ii) regulating, (iii) supporting and (iv) cultural. These four categories will be hereafter referred to as 'ecosystem service domains'. We chose the TEEB classification of ecosystem services over the two other common approaches to classifying ecosystem services—the Millennium Ecosystem Assessment (MEA) and Common International Classification of Ecosystem Services (CI-CES). TEEB is well-known in the context of environmental economics and provides a robust framework for applications in urban planning and policies [53]. Moreover, the TEEB framework emphasises the need for valuing ecosystem services such that the wide range of benefits of ecosystems and biodiversity is recognised by decision-makers [54]. We also recorded the location (e.g., city and country) of studies and quantified the number of times ecosystem service domains were assessed for each country. To analyse the scale of UES assessment, we recorded the population size and area of study sites, scale of assessment as well as distinguished between 'urban' and/or 'peri-urban' areas.

(2) Does UES research focus on single or multiple services and what type of blue-green structure have been assessed?

We recorded the ecosystem services assessed as one of the 17 ecosystem services defined by the TEEB framework [52]. As studies can mention more ecosystem services than those that were empirically assessed, we only classified ecosystem services that were explicitly investigated. We evaluated the number of services assessed in each study and whether the services belonged to the same ecosystem service domain. The ecological structures that provide the investigated ecosystem service(s) were classified as either vegetative (green) or water (blue) structures. We identified 12 categories of blue-green structures, comprising four blue structures (coastal lands, wetlands, rivers, lakes) and eight green structures (urban forests, parks, street greenery, gardens, rooftops, green walls, cultivated lands and grasslands; refer to Table S3 in Supplementary Material for detailed definitions of blue-green structures). structures that provide the investigated ecosystem service(s) were classified as either vegetative (green) or water (blue) structures. We identified 12 categories of blue-green structures, comprising four blue structures (coastal lands, wetlands, rivers, lakes) and eight green structures (urban forests, parks, street greenery, gardens, rooftops, green walls, cultivated lands and grasslands; refer to Table S3 in Supplementary Material for detailed definitions of blue-green structures).

*Land* **2021**, *9*, x FOR PEER REVIEW 6 of 21

(3) Which components of the 'cascade' have been assessed, how are the interactions between UES conceptualised and stakeholders involved? (3) Which components of the 'cascade' have been assessed, how are the interactions between UES conceptualised and stakeholders involved?

The components of ecosystem service 'cascade' were assessed according to structure, function, services, and each linkage between structure-function-services (Figure 1). We described studies as either reviewing one of these six components, all of the six components or none, if studies did not assess any of the components in depth. We recorded the explicit assessment of synergies and tradeoffs in studies as well as the involvement of stakeholders in supporting UES assessments. The latter was defined as the feedback or involvement of external parties, aside from the researcher, in assessing UES. Studies involving surveys and interviews were considered to have involved stakeholders. The components of ecosystem service 'cascade' were assessed according to structure, function, services, and each linkage between structure-function-services (Figure 1). We described studies as either reviewing one of these six components, all of the six components or none, if studies did not assess any of the components in depth. We recorded the explicit assessment of synergies and tradeoffs in studies as well as the involvement of stakeholders in supporting UES assessments. The latter was defined as the feedback or involvement of external parties, aside from the researcher, in assessing UES. Studies involving surveys and interviews were considered to have involved stakeholders.

**Figure 1.** The components and definitions of the cascade model used to classify UES studies [41]. **Figure 1.** The components and definitions of the cascade model used to classify UES studies [41].

> (4) What research perspectives, and data collection and analytical methods are used to assess UES? (4) What research perspectives, and data collection and analytical methods are used to assess UES?

> We assigned each study one of the following six research perspectives: (i) ecology, (ii) social, (iii) planning, (iv) governance, (v) economic and (vi) methods [41]. The definitions for this classification are available in Table S2 in Supplementary Material. Although a single study can be undertaken with more than one perspective, we classified each study by its most dominant research perspective. Data collection methods were classified into four categories: (i) 'field-based empiri-We assigned each study one of the following six research perspectives: (i) ecology, (ii) social, (iii) planning, (iv) governance, (v) economic and (vi) methods [41]. The definitions for this classification are available in Table S2 in Supplementary Material. Although a single study can be undertaken with more than one perspective, we classified each study by its most dominant research perspective.

> ling' and 'land cover proxy' (e.g., remote sensing of land cover), and (iii) 'social surveys'

Data collection methods were classified into four categories: (i) 'field-based empirical', (ii) 'biophysical modelling' which is sub-divided into 'process/mechanistic modelling' and 'land cover proxy' (e.g., remote sensing of land cover), and (iii) 'social surveys' and (iv) case studies. We also recorded the type of data collected (i.e., 'quantitative', 'qualitative', or 'both') and the temporal focus of the study. Studies were also reviewed for the valuation of UES and where valuations were conducted, we distinguished between 'monetary valuation' (i.e., economic) and/or 'non-monetary valuation' (i.e., social or biophysical). *Land* **2021**, *9*, x FOR PEER REVIEW 7 of 21 and (iv) case studies. We also recorded the type of data collected (i.e., 'quantitative', 'qualitative', or 'both') and the temporal focus of the study. Studies were also reviewed for the valuation of UES and where valuations were conducted, we distinguished between 'monetary valuation' (i.e., economic) and/or 'non-monetary valuation' (i.e., social or biophysical).

#### **3. Results 3. Results**

#### *3.1. Distribution and Scale of UES Assessment across Southeast Asia 3.1. Distribution and Scale of UES Assessment across Southeast Asia*

Of the 149 studies reviewed in Southeast Asia, 29% were conducted in Singapore (n = 44), followed by 22% in Indonesia (n = 33). Myanmar (n = 4) and Timor Leste (n = 1) had very few studies, while no published studies from Brunei were returned in the search (Figure 2). About 64% of studies had authors with their primary research institution in Southeast Asia (n = 95), with 59% of studies conducted in the country where their primary research institution was located. As for studies with authors' primary research institutions located outside of Southeast Asia, 16% of authors were based in Europe (n = 24), 11% in other parts of Asia (n = 17) (mainly East Asia), 5% in North America (n = 8) and 3% in Australia (n = 5). Note the possibility of some bias in this analysis due to the inclusion of only studies published in English. Of the 149 studies reviewed in Southeast Asia, 29% were conducted in Singapore (n = 44), followed by 22% in Indonesia (n = 33). Myanmar (n = 4) and Timor Leste (n = 1) had very few studies, while no published studies from Brunei were returned in the search (Figure 2). About 64% of studies had authors with their primary research institution in Southeast Asia (n = 95), with 59% of studies conducted in the country where their primary research institution was located. As for studies with authors' primary research institutions located outside of Southeast Asia, 16% of authors were based in Europe (n = 24), 11% in other parts of Asia (n = 17) (mainly East Asia), 5% in North America (n = 8) and 3% in Australia (n = 5). Note the possibility of some bias in this analysis due to the inclusion of only studies published in English.

**Figure 2.** Number of UES studies in Southeast Asia and percentage of urban population in each country. Not visible in the map is the percentage of urban population in Singapore, which is 100%. No studies from Brunei were reviewed. **Figure 2.** Number of UES studies in Southeast Asia and percentage of urban population in each country. Not visible in the map is the percentage of urban population in Singapore, which is 100%. No studies from Brunei were reviewed.

77% of studies are concentrated in four cities; the city-state of Singapore was most frequently studied (n = 44), followed by the metropolitan capital cities of Bangkok in Thailand (n = 13), Jakarta in Indonesia (n = 12) and Kuala Lumpur in Malaysia (n = 8). In terms 77% of studies are concentrated in four cities; the city-state of Singapore was most frequently studied (n = 44), followed by the metropolitan capital cities of Bangkok in Thailand (n = 13), Jakarta in Indonesia (n = 12) and Kuala Lumpur in Malaysia (n = 8).

of the type of urban area assessed, 76% of studies were conducted in fully urban areas (n

urban areas (n = 13). Around 43% of studies were conducted at a 'single-city scale' (n = 64), followed by 32% at the 'sites within cities' scale (n = 48) (Figure 3). Only 17% of studies

In terms of the type of urban area assessed, 76% of studies were conducted in fully urban areas (n = 113), 15% in peri-urban areas (n = 23) and 8% of studies spanned both urban and peri-urban areas (n = 13). Around 43% of studies were conducted at a 'single-city scale' (n = 64), followed by 32% at the 'sites within cities' scale (n = 48) (Figure 3). Only 17% of studies assessed multiple cities (n = 26) and 7% of studies were conducted at scales larger than cities (i.e., regional or continental scales) (n = 11). Study area sizes varied markedly, extending from a few square kilometres to tens of millions of square kilometres. Similarly, population sizes within the study areas differed greatly, from 750 (Botoc village, Philippines) to 9.6 million (Jakarta metropolitan). *Land* **2021**, *9*, x FOR PEER REVIEW 8 of 21 assessed multiple cities (n = 26) and 7% of studies were conducted at scales larger than cities (i.e., regional or continental scales) (n = 11). Study area sizes varied markedly, extending from a few square kilometres to tens of millions of square kilometres. Similarly, population sizes within the study areas differed greatly, from 750 (Botoc village, Philippines) to 9.6 million (Jakarta metropolitan).

**Figure 3.** The general characteristics of UES research. (**A**) The various scales at which UES were assessed; (**B**) The percentage of studies conducted by authors based in and outside of Southeast Asia (denoted by the country in which the primary institution of the first author is located); (**C**) The assessment of UES within and/or across domains; (**D**) The types bluegreen structures assessed; (**E**) The temporal focus of the study where 'single temporal focus' represents studies that examined UES at one point/period in time and 'multitemporal' represents studies that compared UES across time; (**F**) The methods of data collection and analysis of UES; and (**G**) The types of UES valuations conducted by studies. **Figure 3.** The general characteristics of UES research. (**A**) The various scales at which UES were assessed; (**B**) The percentage of studies conducted by authors based in and outside of Southeast Asia (denoted by the country in which the primary institution of the first author is located); (**C**) The assessment of UES within and/or across domains; (**D**) The types blue-green structures assessed; (**E**) The temporal focus of the study where 'single temporal focus' represents studies that examined UES at one point/period in time and 'multitemporal' represents studies that compared UES across time; (**F**) The methods of data collection and analysis of UES; and (**G**) The types of UES valuations conducted by studies.

Of the four domains, regulating (36%) and cultural (26%) services were most assessed. Most countries had studies encompassing services across all four domains; exceptions were Laos and Timor Leste (Figure 4a). Studies comprised all 17 ecosystem services

quently studied service (n = 54), followed by the 'moderation of extreme events' service (n = 51). The 'medicinal resources' and 'biological control' services were least assessed, with only 5 and 4 studies respectively (Table 2). Most studies took a multi-domain approach (n = 67) by investigating ecosystem services across multiple domains. Around 42%

*3.2. Services and Blue-Green Structures Assessed* 

#### *3.2. Services and Blue-Green Structures Assessed*

Of the four domains, regulating (36%) and cultural (26%) services were most assessed. Most countries had studies encompassing services across all four domains; exceptions were Laos and Timor Leste (Figure 4a). Studies comprised all 17 ecosystem services across all domains, with the 'recreation and mental and physical health' as the most frequently studied service (n = 54), followed by the 'moderation of extreme events' service (n = 51). The 'medicinal resources' and 'biological control' services were least assessed, with only 5 and 4 studies respectively (Table 2). Most studies took a multi-domain approach (n = 67) by investigating ecosystem services across multiple domains. Around 42% of studies assessed a single ecosystem service (n = 63), while 13% studied multiple services from a single domain (n = 19).

60% of studies assessed a single blue-green structure (n = 90) while the remaining studies assessed two or more structures; the maximum was seven structures (n = 2) (Figure 4b). Of the 12 blue-green structures, parks were most frequently studied (n = 57), followed by wetlands (n = 45) and urban forests (n = 44) (note: values differ from the number of times each structure was studied under ecosystem service domains, see Figure 4b). All 12 structures were studied across the four ecosystem services domains except for green walls, which were not studied for provisioning services. Rivers, urban forests and cultivated lands were most commonly studied for provisioning services, while street greenery and wetlands were commonly studied for regulating services. Parks were almost equally studied for regulating (n = 39) and cultural services (n = 36), although studies of cultural services pre-dominantly assessed parks in comparison to all other structures (23%). *Land* **2021**, *9*, x FOR PEER REVIEW 9 of 21 of studies assessed a single ecosystem service (n = 63), while 13% studied multiple services from a single domain (n = 19).

**Figure 4.** Ecosystem service domains assessed according to (**a**) countries and, (**b**) blue-green structures. Tourism 19 **Figure 4.** Ecosystem service domains assessed according to (**a**) countries and, (**b**) blue-green structures.

**Provisioning** 

**Regulating** 

fication system [52]. Note that some studies assessed multiple ecosystem services; thus, the total

**Domain Ecosystem Service Number of Studies** 

Food 40 Raw materials 29 Fresh water 18 Medicinal resources 4

Local climate and air quality 44 Carbon sequestration and storage 27 Moderation of extreme events 51 Wastewater treatment 11

Maintenance of genetic diversity 8

Pollination 9 Biological control 5

Erosion prevention and maintenance of soil fertility 15

**Supporting** Habitats for species 43

**Cultural** Recreation and mental and physical health 54

number of ecosystem services assessed is greater than the 149 publications reviewed.


**Table 2.** The number of studies that assessed each ecosystem service according to the TEEB classification system [52]. Note that some studies assessed multiple ecosystem services; thus, the total number of ecosystem services assessed is greater than the 149 publications reviewed.

#### *3.3. Components of the 'Cascade' and Stakeholder Involvement*

Only 2% of studies (n = 3) did not assess any component of the cascade in depth. These studies were mainly on the management of ecosystem services using frameworks that did not focus on any specific component of the cascade (e.g., [55,56]). Conversely, 16% of studies (n = 24) assessed all three components (Table 3). For instance, Remondi [57] simulated changes to land use surrounding rivers in Jakarta under different urbanisation scenarios. The study modelled the capacity of the river (structure) to retain water (function), in providing fresh water and flood protection services to the local population (services and benefits). The most studied component was the structure-function linkage (26% of studies; n = 38), while the function component was least assessed, with only 4% of studies (n = 6). Only 4% (n = 6) of the 149 studies had explicitly investigated ecosystem service interactions such as synergies and tradeoffs. The majority of the studies (56%) did not involve stakeholders either through surveys, interviews or expert input. Of those that did, most assessed cultural services (n = 46). Links between UES and climate change were only assessed by 3% of studies (n = 5).

**Table 3.** Distribution of the number of studies assessing various components of the ecosystem services cascade.


#### *3.4. Research Perspectives and Methods of UES Assessment*

The number of studies in the region has increased across all ecosystem service domains (Figure 5a), particularly over the last decade; the review only yielded three studies prior to 2011 (Figure 5b), with more than 89% being published post-2014 (n = 133). The highest annual number of studies was in the year 2018, although bearing mind that for 2020 the review only included studies published between January and August, this year also saw a relatively high number of papers published. *Land* **2021**, *9*, x FOR PEER REVIEW 11 of 21

**Figure 5.** The (**a**) ecosystem service domains and (**b**) research perspectives, undertaken by studies over time. Note: A study may have assessed more than one ecosystem service domain but only one research perspective. Hence, Figure 5**b** represents the actual number of studies reviewed over **Figure 5.** The (**a**) ecosystem service domains and (**b**) research perspectives, undertaken by studies over time. Note: A study may have assessed more than one ecosystem service domain but only one research perspective. Hence, **b** represents the actual number of studies reviewed over time.

time.

Only papers published between 2018 and 2020 encompass all six research perspectives. Of the 149 studies, 32% were dominated by an ecological perspective (n = 47), while studies undertaken with a governance perspective were least common (3%; n = 5). Since 2013, more studies have been undertaken with social and planning perspectives, while governance-based research has received more attention since 2017. Studies with an eco-Only papers published between 2018 and 2020 encompass all six research perspectives. Of the 149 studies, 32% were dominated by an ecological perspective (n = 47), while studies undertaken with a governance perspective were least common (3%; n = 5). Since 2013, more studies have been undertaken with social and planning perspectives, while governance-based research has received more attention since 2017. Studies with an ecological perspective were conducted in all countries except Timor Leste, which had the least

comprised 43% (n = 10) of studies in this country.

etnam had studies comprising all six perspectives. About 34% (n = 15) of the 44 studies conducted in Singapore had an ecological perspective, while only 5% (n = 2) had an economic perspective and one study had a governance perspective. There were no studies with an economic or governance perspective in Malaysia, although the social perspective *Land* **2021**

number of studies in the region (Figure 6a). Singapore, Indonesia, Thailand and Vietnam had studies comprising all six perspectives. About 34% (n = 15) of the 44 studies conducted in Singapore had an ecological perspective, while only 5% (n = 2) had an economic perspective and one study had a governance perspective. There were no studies with an economic or governance perspective in Malaysia, although the social perspective comprised 43% (n = 10) of studies in this country. , *9*, x FOR PEER REVIEW 12 of 21

Street greenery, gardens and rooftops were mainly studied from an ecological perspective, while parks, urban forests and rivers were predominantly assessed from a methods perspective (Figure 6b). Wetlands were most studied under the governance perspective (n = 9) and two of four studies of green walls had a planning perspective. Cultivated lands were equally studied using methods and ecological perspectives. Street greenery, gardens and rooftops were mainly studied from an ecological perspective, while parks, urban forests and rivers were predominantly assessed from a methods perspective (Figure 6b). Wetlands were most studied under the governance perspective (n = 9) and two of four studies of green walls had a planning perspective. Cultivated lands were equally studied using methods and ecological perspectives.

Over 89% of studies (n = 133) examined UES in a single time period or duration, with only 16 studies comparing services over two or more points in time. With respect to the type of data collected, 65% of studies (n = 97) collected only quantitative data, while only 5% of studies (n = 8) examined qualitative data. The remaining 44 studies examined both qualitative and quantitative data. Process and/or mechanistic models were the most utilised method of data collection and analysis in the region, comprising 88 studies (note: studies can utilise more than one method). Social surveys were the next most common Over 89% of studies (n = 133) examined UES in a single time period or duration, with only 16 studies comparing services over two or more points in time. With respect to the type of data collected, 65% of studies (n = 97) collected only quantitative data, while only 5% of studies (n = 8) examined qualitative data. The remaining 44 studies examined both qualitative and quantitative data. Process and/or mechanistic models were the most utilised method of data collection and analysis in the region, comprising 88 studies (note: studies can utilise more than one method). Social surveys were the next most common

UES and 8 studies used landcover proxies. Only 23% (n = 34) of studies conducted valuations, of which over half were monetary (n = 19). Two studies conducted both monetary and non-monetary valuations, while the remaining studies (n = 12) conducted non-mon-

etary valuations.

*4.1. Current State of Research*

**4. Discussion** 

method (n = 43), followed by field sampling (n = 33). 13 studies used case studies to assess UES and 8 studies used landcover proxies. Only 23% (n = 34) of studies conducted valuations, of which over half were monetary (n = 19). Two studies conducted both monetary and non-monetary valuations, while the remaining studies (n = 12) conducted non-monetary valuations.

#### **4. Discussion**

#### *4.1. Current State of Research*

Our review found that the there was a growing body of research on UES in the Southeast Asia, particularly in the last five years. The research was biased towards more developed countries, in particular the city-state of Singapore, where about one third (29%) of published research was conducted. Previous reviews have also found that UES research tends to focus on highly developed and urbanised countries [28,41]. It is also apparent that little research has been conducted in less developed countries such as Myanmar, Cambodia and Laos. While most papers were authored by researchers based in Southeast Asia, there were no clear differences between the research foci of authors based in Southeast Asia and those based outside of the region.

Studies in Southeast Asia provided sufficient contextual information in their assessment, contrary to the findings of Luederitz [41] in their global review. Studies provided detailed descriptions of the boundary of respective the study areas, population size, location of ecological structures and type of structures studied. Of the four ecosystem service domains, in Southeast Asia, regulating and cultural services were predominantly assessed (62% of all studies). The two most commonly assessed services were recreation, mental and physical health (n = 54) and moderation of extreme events services (n = 51). Parks were the most assessed blue-green structure, while there were few studies focused on coastal areas (n = 12), rooftops (n = 7) and green walls (n = 4).

Over half the studies examined multiple ecosystem services, within and across domains, and mostly at a landscape scale (i.e., city scale or larger). Studies also assessed multiple components of the cascade, although there is room for a more holistic research approach, as interactions, such as synergies and tradeoffs between services were rarely examined (4%). There was also a lack of studies with a multitemporal focus (11%). Process/mechanistic modelling was the dominant method of UES assessment [58–60], although valuations of services were lacking.

Stakeholder involvement was higher in studies that examined regulating and cultural services. Many studies that involved stakeholders also had social or planning research perspectives suggesting a strong applied focus on managing UES. There were few studies with a dominant governance perspective and this finding is not unique to Southeast Asia, as global reviews by Haase [28] and Luederitz [41] also report the lack of governance discourse on UES research. While the nature of UES research within the region may have some commonalities with its global counterpart, we highlight aspects of research that are specific to Southeast Asia, discussing considerations and opportunities for integrating UES in the region below.

#### *4.2. Specificity of Research in Southeast Asia*

The transferability of research may be limited due to the diverse characteristics of Southeast Asian countries—in particular economic power and government effectiveness (see Table 1 and Figure 2) [17]. Furthermore, even within countries there can be diversity in values. There is diversity in environmental conditions as well as the nature of urbanisation and cultural perspectives and values. For example, Hassan [61] highlighted substantial differences in wetland management preferences between urban and rural areas in Malaysia. While, in Singapore, contrary to popular assumptions around the desire for natural green spaces, some urban residents do not favour high conservation value vegetation and unmanaged secondary forests due to perceived wildlife threats and poor aesthetics [62,63].

If regional uniformity is assumed in how services are perceived and valued, the specific preferences and/or needs of minority groups may be overlooked when managing UES.

Considering that countries in Southeast Asia are renowned agro-industrial producers and exporters [64], provisioning services and services from agricultural landscapes (e.g., oil palm) were fairly understudied in the region. Although it is generally expected that highly urbanised areas are less likely to include productive areas, agricultural landscapes can be commonly found within the urban matrix of Southeast Asia [65,66]. While this adds to the uniqueness of urban-scapes in the region, the interactions between provisioning services and other service types, as well as implications for different stakeholders is yet to be fully understood.

Much remains to be learnt about biodiversity and UES in Southeast Asia. As Mammides [67] reported, despite most of the world's biodiversity being concentrated in the tropics and the imminent threats it faces, research on tropical conservation is largely underrepresented. In our review, the initial search string, which contained only UES related terms, returned only 48 relevant publications. It was only through expanding our search string with more general keywords that we were able to increase the number of publications. Like most other Global South regions, the underrepresentation of research could be attributed to Southeast Asia being data poor [68,69], which was noted in a number of studies [62,70,71].

Limitations in the quality, availability and access to data pose major challenges to UES research in the region. Databases and organisations that collect and provide openaccess regional environmental data are few to none, compared to those in North America or Europe (e.g., United States Geological Survey, European Soil Data Centre, National Biodiversity Network, Biodiversity Information System for Europe, European Environment Agency). This was reported in several studies such as Balmford [72] who used global environmental data in their assessment of road networks in the Greater Mekong subregion, as finer scale, regional data was not available. Estoque [70] also utilised global ecosystem service values reported by Costanza [73] due to the limited availability of local data in Baguio, Philippines. Estoque [74] highlighted the need for available and accessible city-scale data across Philippines for conducting heat vulnerability assessments, while Belcher and Chisholm [62] reported that in Singapore LULC data is not publicly available. This limitation significantly affects research outputs as collection and generation of highresolution regional data requires important human and time resources.

#### **5. Conclusions: Research Needs to Move Forward**

As Southeast Asian cities grow and the population density in urban areas rise, demand for ecosystem services will become increasing important [75]. The recognised importance of UES is also seen with the increased number of UES assessments in the region over the last decade (Figure 5b). Increasing urbanisation and urban sprawls in Southeast Asia often result in the loss of natural ecosystems due to the infrastructure demands of growing urban populations [17]. Conserving nature and supporting the provision of UES is often more cost effective and practical than restoring degraded ecosystems [76,77], so a worthwhile objective for cities in the region is avoiding the loss of natural ecosystems through the consideration of UES in planning.

The prevalence of certain services within UES research suggests some UES are considered to be more important than others, from a research perspective, in the Southeast Asian context. For instance, the preservation of cultural services such as recreation services (n = 54) and aesthetic appreciation (n = 44), which are strongly associated with green spaces [33,78], may be of high interest to urban residents, as these areas are being rapidly lost to high density development patterns, characteristic of urbanisation in Southeast Asian cities [79,80]. Similarly, climate regulating services (n = 44) appear to be valued for their role in reducing urban heat island effects, which is a common issue in the region's densely urbanised tropical cities, with high average temperatures [81–84]. These UES, which have

been the focus of research, may be valued for their direct contribution to the wellbeing of urban populations and liveability of cities [33,85,86].

Recent research on the nexus between urban challenges, UES and Nature-based Solutions [17,87,88], highlights the role of UES in improving the liveability, resilience and sustainability of cities [15,89]. However, the future availability of UES is determined by land use decisions made in urban planning [90], which need to be supported by exhaustive assessments of UES. Thus, we highlight the following research areas, based on our review, that need further attention in order for UES research to wholly support land use planning and decision-making in the region (Figure 7). *Land* **2021**, *9*, x FOR PEER REVIEW 15 of 21

#### i) Geographically representative assessments (i) Geographically representative assessments

UES research is biased towards specific countries, regions and cities (Figure 2; Figure 4a). Aside from socioeconomic characteristics (Table 1), there are major biophysical differences between locations with maritime, continental and island climates in the region. This means that research conducted in Singapore may not necessarily be applicable in Cambodia or Myanmar. UES research needs to be context specific in order to purposefully address local needs. We therefore stress the need for a diverse range of UES assessments in countries that have very low representation of research such as Myanmar (n = 9), Laos (n = 1), Timor-Leste (n = 1) and Brunei (n = 0). The focus of assessments should also expand from megacities to secondary cities that are underrepresented (77% of studies concentrated on only four megacities—Singapore, Bangkok, Jakarta and Kuala Lumpur). UES research is biased towards specific countries, regions and cities (Figure 2; Figure 4a). Aside from socioeconomic characteristics (Table 1), there are major biophysical differences between locations with maritime, continental and island climates in the region. This means that research conducted in Singapore may not necessarily be applicable in Cambodia or Myanmar. UES research needs to be context specific in order to purposefully address local needs. We therefore stress the need for a diverse range of UES assessments in countries that have very low representation of research such as Myanmar (n = 9), Laos (n = 1), Timor-Leste (n = 1) and Brunei (n = 0). The focus of assessments should also expand from megacities to secondary cities that are underrepresented (77% of studies concentrated on only four megacities—Singapore, Bangkok, Jakarta and Kuala Lumpur).

ii) Assessments on peri-urban areas and synergies and tradeoffs (ii) Assessments on peri-urban areas and synergies and tradeoffs

As cities expand, peri-urban areas experience rapid land use change. However, only 15% of assessments examined peri-urban areas, consistent with Richards [91] and Wangai [75] that highlight peri-urban areas as being understudied globally. We encourage UES research in peri-urban areas, as these areas are where the intensity of development is the greatest and UES are being lost or degraded, and therefore where planning is mostly urgently needed. It is especially important to investigate the synergies and tradeoffs of UES in urban As cities expand, peri-urban areas experience rapid land use change. However, only 15% of assessments examined peri-urban areas, consistent with Richards [91] and Wangai [75] that highlight peri-urban areas as being understudied globally. We encourage UES research in peri-urban areas, as these areas are where the intensity of development is the greatest and UES are being lost or degraded, and therefore where planning is mostly urgently needed.

and peri-urban areas so the consequence of planning decisions can be considered systematically [92,93]. Although 58% of studies in the region assessed multiple ecosystem services, only 4% dealt with synergies and tradeoffs. A clear understanding of the complex interactions between UES, as well as UES and land use management, is particularly im-It is especially important to investigate the synergies and tradeoffs of UES in urban and peri-urban areas so the consequence of planning decisions can be considered systematically [92,93]. Although 58% of studies in the region assessed multiple ecosystem services, only 4% dealt with synergies and tradeoffs. A clear understanding of the complex interac-

We also highlight the need for synergy and tradeoffs assessments between urbanisation and provisioning services. The spatial expansion of cities has negative impacts on urban/peri-urban agriculture [94], which is commonplace in Southeast Asia [66,95]. Given the importance of agricultural production to local livelihood in the region [96], the sustainability and multifunctional capacity of urban agricultural landscapes needs to be better understood [97,98]. Careful management of land use as peri-urban areas develop can yield more sustainable UES provision, than attempts to retrofit restoration efforts in the

future.

iii) Assessments on coastal areas

tions between UES, as well as UES and land use management, is particularly important in rapidly developing peri-urban areas.

We also highlight the need for synergy and tradeoffs assessments between urbanisation and provisioning services. The spatial expansion of cities has negative impacts on urban/peri-urban agriculture [94], which is commonplace in Southeast Asia [66,95]. Given the importance of agricultural production to local livelihood in the region [96], the sustainability and multifunctional capacity of urban agricultural landscapes needs to be better understood [97,98]. Careful management of land use as peri-urban areas develop can yield more sustainable UES provision, than attempts to retrofit restoration efforts in the future.

#### (iii) Assessments on coastal areas

Many of Southeast Asia's densely populated cities are located along the coastlines (e.g., Greater Jakarta, Singapore, Ho Chi Minh, Bangkok, Manila), yet few studies examined UES in coastal areas. Coastal cities are particularly vulnerable to coastal and riverine floods, coastal erosion, storm surges, monsoons and tsunamis [99,100], all of which bring adverse health risks to the urban population [101,102]. Moreover, many of these extreme events are expected to increase in frequency in Southeast Asia because of climate change effects [14,99]. Thus, we bring to attention the exigency of assessments of coastal structures as a Naturebased Solution in coastal cities. Research should also focus on opportunities to support the resilience of urban communities through the sustainable provision of UES [103].

(iv) Multi-temporal, climate-sensitive and scenario-based assessments

Few studies (11%) have conducted temporal assessments of UES, which are key to understanding changes in service provision and demand [104]. This is challenging in practice as there is limited information on how UES change over time and/or under different future scenarios [57,105]. Moreover, Southeast Asian cities are seen to be highly vulnerable to climate change effects [17,106,107], yet few studies have examined the link between UES and climate resilience (n = 5). Assessments of changes in UES can be used to identify areas vulnerable to weather-related disaster risks and/or support decisions on appropriate land use management strategies [14]. Our review highlights a pressing need for multitemporal and/or scenario-based research on the resilience of UES provision. Research should also address the increased risk of diseases in tropical ecosystems due to the effects of climate change [108,109], as well as the consequent impacts to UES, particularly provisioning services [110,111].

#### (v) Diverse valuations and increased stakeholder involvement

Literature supporting the valuation of ecosystem services is abundant [30,112–114], with recent research emphasising diverse perspectives in valuations through value pluralism [49]. However, our review found that only 23% of studies in the region conducted valuations. Valuations support decision-making by providing explicit quantification of UES demand, which can be in monetary or non-monetary terms [46]. The involvement of stakeholders (44%) in UES assessments can support valuations by identifying context-specific demands and preferences of the people appropriating the services [41,49].

In line with TEEB and the Intergovernmental Panel on Biodiversity and Ecosystem Services (IPBES) [49,115,116], we urge research to incorporate diverse valuations, monetary and non-monetary, as well as increase stakeholder involvement in UES assessments. Although contentious [117], the comprehensive representation of UES through valuations has been proven to be effective in influencing decision-makers towards planning agendas [118]. This is because valuations can be used as a tool to demonstrate the cost of restoring ecosystems or the critical importance of alternative land use options objectively to decision-makers [119–121]. As the invisibility of nature in economic choices often drives its depletion [53], valuation of UES can encourage more transparent assessments of tradeoffs to support the planning of sustainable cities.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/2073-445 X/10/1/40/s1, Search strings for Scopus and Web of Knowledge databases; Table S1: Bibliography of the 149 studies analysed in this review; Table S2: Review categories, description and classification method; Table S3: Ecological structures and definitions.

**Author Contributions:** This review is part of a PhD research by K.T.L. The idea for the paper was conceived by K.T.L., A.M.L. and C.N.G., K.T.L. performed the literature search, data analysis and drafted the original manuscript. A.M.L., C.N.G., P.H., R.S. and B.A. provided critical feedback and edited the manuscript. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work is part of a PhD research that is funded by the Faculty of Science and Engineering and the Landscape Ecology and Conservation Laboratory, School of Environmental and Geographical Sciences at the University of Nottingham Malaysia. We are also thankful for the funding received from the International Research Collaboration Award from the Research Knowledge and Exchange Hub, University of Nottingham Malaysia, Singapore's National Research Foundation (NRFF12-2020- 0009) and the Putra Grant-Putra Young Initiative (IPM) from Universiti Putra Malaysia (Grant No: GP-IPM/2018/9637800).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available within the article and supplementary materials.

**Acknowledgments:** We thank the reviewers for their kind and constructive feedback which has helped improve the manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


## *Article* **Governance, Nature's Contributions to People, and Investing in Conservation Influence the Valuation of Urban Green Areas**

**Alexandra Pineda-Guerrero <sup>1</sup> , Francisco J. Escobedo 2,\* and Fernando Carriazo <sup>3</sup>**


**Abstract:** There is little information concerning how people in the Global South perceive the benefits and costs associated with urban green areas. There is even less information on how governance influences the way people value these highly complex socio-ecological systems. We used semistructured surveys, statistical analyses, and econometrics to explore the perceptions of users regarding governance and the benefits and costs, or Ecosystem Services (ES) and Ecosystem Disservices (ED), provided by Neotropical green areas and their willingness to invest, or not, for their conservation. The study area was the El Salitre sub-watershed in Bogota, Colombia, and 10 different sites representative of its wetlands, parks, green areas, and socioeconomic contexts. Using a context-specific approach and methods, we identified the most important benefits and costs of green areas and the influence of governance on how people valued these. Our modelling shows that air quality and biodiversity were highly important benefits, while water regulation was the least important; despite the subwatershed's acute problems with stormwater runoff. In terms of costs, the feeling of insecurity due to crime was related to poor levels of maintenance and infrastructure in the studied green areas. Perceived transparency, corruption, and performance of government institutions influenced people's Unwillingness to Invest (UTI) in green space conservation. Results show that socioeconomic backgrounds, government performance, and environmental education will play a role in the value or importance people place on the benefits, costs, and UTI in conservation efforts in urban green areas. Similarly, care is warranted when directly applying frameworks and typologies developed in high income countries (i.e., ES) to the unique realities of cities in the Global South. Accordingly, alternative frameworks such as Nature's Contributions to People is promising.

**Keywords:** urban biodiversity; urban watersheds; Bogota Colombia; corruption; Unwillingness to Invest

#### **1. Introduction**

The link between human well-being and urban green areas, forests, parks, wetlands, and other natural and semi-natural ecosystems in cities has been well established [1,2] Several studies have valued multiple benefits using a diverse set of case studies, methods, and ecosystem service frameworks like the Millennium Ecosystem Assessment, The Economics of Ecosystem and Biodiversity, and others [3]. These have classified and defined urban ecosystem services as well as reviewed methods for their valuation. A similar body of literature has also discussed ecosystem disservices, or the social, environmental, and economic costs that these detrimental ecosystem functions have on people's well-being [4–6].

This urban ecosystem service–disservice literature has primarily used case studies in contexts such those of Europe and the United States to explore these functions as well as the links between citizens and the benefits from green spaces [7–9] Similarly, several

**Citation:** Pineda-Guerrero, A.; Escobedo, F.J.; Carriazo, F. Governance, Nature's Contributions to People, and Investing in Conservation Influence the Valuation of Urban Green Areas. *Land* **2021**, *10*, 14. https://dx.doi.org/10.3390/ land10010014

Received: 30 November 2020 Accepted: 23 December 2020 Published: 27 December 2020

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/ licenses/by/4.0/).

urban ecological functions result in a suite of disservices and costs including: Human injuries and infrastructure damage from vegetation debris and growth, wildlife nuisance, allergies, and maintenance costs, among others [6,10,11]. More recently, because cities are complex socio-ecological systems, other socioeconomic functions—in addition to ecological ones—are being included in the assessment of urban ecosystem disservices and can include: Fear of crime and tree fall, unpleasing aesthetics, diseases from remnant natural areas (i.e., wetlands) and foregone property premiums to name a few [6,7,12]. Despite this, there is much less information on how people in the Global South perceive benefits [13–16], and even less so on ecosystem disservices and if conventional urban ES/ED typologies are relevant for green areas of the Global South [17,18].

More recently, the Intergovernmental Panel on Biodiversity and Ecosystem Services has proposed the Nature's Contributions to People (NCP) framework or "the positive contributions, or benefits, and occasionally negative contributions, losses or detriments, that people obtain from nature" to complement the ecosystem service framework; particularly in places like the Global South [16]. Although NCP "goes further by explicitly embracing concepts associated with other worldviews on human–nature relations and knowledge systems" [16], the concept has sparked a lively debate in the ecosystem service community; see [18] and responses therein to the article. Despite this recent NCP versus ecosystem services controversy, the terms "benefits" and "costs" as related to urban green areas have a long history of use and application dating back to the early 1990s [1] before the advent and frequent use of these other metaphors [17].

Other studies regularly use geospatial and statistical methods to understand the supply of these ecosystem services and benefits in cities [19,20]. Surveys are also regularly used to better understand the perception residents have towards urban ecosystem services [6,15]. Some of these studies use psychometric scales and methods [15], as well as stated preferences and econometrics, to determine value [6,21]. Fewer studies have, however, measured the role that governance, perceived corruption, and policy processes have in influencing people's willingness to pay to conserve the ecosystems providing such benefits [22,23]. Similarly, the realities of inequity, weak governance, perceived corruptions, and lack of resources is systematically omitted in stated preference studies in low–middle income countries [21].

These processes and dynamics between actors or stakeholders, governments, and the management and planning of these benefits are key elements that link the supply and demand for benefits [24]. These policy processes, or governance, of ecosystem benefits has been looked at using several lenses including: Political ecology [25,26], urban and rural forest management [27,28], biodiversity [22,24], program evaluation, and the urban ecosystem services framework [8,9,11,29]. However, most of these urban context studies are predominantly from high income countries such as those of North America, Europe, and Australia [17].

The concept of governance has many definitions and applications, and has been described as "an emergent, often complex decision making process" [30]. Huang, C.W. et al. [24] define effective governance as a process that "facilitates the development and implementation of law, regulations, and institutions that have a role in the management of land resources". Although generally used as a means to describe the processes used by governments to include the governed or society in the decision making process (state-centered), it can also include community and market sectors and situations where actors take a prominent role in the co-management of ecosystems (society-centered; [25,27]). Governance as such includes processes and interactions that organize power relations, influences, interests, and government performance and transparency into the decision making process in order to determine socioeconomic and environmental benefits [28].

Lawrence, A., et al. [28] and Launay, G.C. et al. [31] emphasize the role of measuring these processes, their applications, and outcomes in terms of evaluating the effectiveness in assuring good governance. Kenward, R.E. et al. [22] and Huang, C.W. et al. [24] investigated the performance of governance strategies and context in achieving successful biodiversity conservation outcomes and supplies of ecosystem services. However, Turnhout, E. et al. [26] argue that an increased focus on measuring transparency, efficiency, and effectiveness can lead to an "impoverished understanding of biodiversity itself". Examples of frameworks, models, and discourses related to governance in regards to urban and peri-urban forests are discussed in detail in [28,32].

However, few studies discuss what good governance is in regards to urban ecosystems in cities of the Global South [13,20,33]. Lockwood [34] defines "good governance", which encompasses: Legitimacy, transparency, accountability, inclusiveness, fairness, connectivity, and resilience, while [31] promoting criteria such as transparency, corruption, and government performance when evaluating proper governance in Latin American countries. According to Barrett, C.B. et al. [35], the inverse of transparency, or corruption, in regards to natural resources is regularly used as an explanation for environmental degradation. Indeed, in low and middle income countries, perceptions of corruption influence how people value and access environmental benefits in both urban and rural settings [21]. Yet, corruption comes in many forms, levels, and scales, and the causal effects and relationships between corruption and natural resource use and condition can be complex [35].

The above studies document how people perceive and value urban ecosystem services in several cities [1,12], and the role of good governance and willingness to pay for conserving biodiversity and ecosystems [9,24,33,36]. However, as previously mentioned, less known is how people in places such as Latin America perceive this urban benefit-cost bundle and how context-specific realities such as lack of transparency, perceived corruption, and inequity affect people´s willingness to invest in conserving the ecosystems that provide these services [17,20]. Indeed, even the relevance and direct application of the ecosystem service framework in places such as the Global South have recently been questioned [13,18].

This study explores how people perceive the benefits, costs, and the influence of governance on their willingness to invest—or not—to conserve urban green areas. We surveyed representative areas in an urbanized sub-watershed in Bogota, Colombia. Specifically, we have three different study objectives. First, we assess how people perceive urban benefits and costs in an urban sub-watershed in Latin America. Second, we assess how socioeconomic factors affect perceptions. Third, we explore the influence of the different dimensions of governance (e.g., perceived corruption, transparency, government performance) on people´s willingness to invest for the conservation of the green areas and wetlands providing these benefits and costs (i.e., Ecosystem Services–Ecosystem Disservices (ES–ED)). So as to avoid the ecosystem service versus NCP controversy [18], we use the terms urban "benefits" and "costs" as defined by Dwyer et al. [1] in our study and analyses; but we do discuss the relevance of these metaphors (i.e., ES, ED, and NCP) in our Discussion and Conclusion with a focus on the promising use of NCP.

#### **2. Materials and Methods**

#### *2.1. Study Area*

The study area was the El Salitre urban sub-watershed in Bogotá, Colombia (Figure 1). Bogotá is located at 2600 m in elevation and has a subtropical highland climate temperature that varies between 7–17 degrees C, and total average annual rainfall is about 825 mm [37]. The study´s sub-watershed encompasses the localities of Usaquén, Santa Fé, Chapinero, Teusaquillo, Barrios Unidos, Engativá, and Suba, and within these are 1894 different neighborhoods encompassing 11,791 has. Although the sub-watershed does encompass a large portion of the adjacent Eastern Hills Protected Forest Area (i.e., Reserva Forestal Protectora Bosque Oriental de Bogotá) to the east of Bogota, the study was done entirely in the urban portion. The El Salitre River is mostly channelized in this urban portion and is often referred to as the Arzobispo, Quebrada Molinos, Rio Callejas, and La Sirena streams or drainage channels. There are four officially designated wetlands and approximately 175 different parks and water bodies within the watershed. In all, 3 wetlands, 5 parks, and 2 green areas were selected for sampling the sub-watershed (Table 1).

Forestal Protectora Bosque Oriental de Bogotá) to the east of Bogota, the study was done entirely in the urban portion. The El Salitre River is mostly channelized in this urban portion and is often referred to as the Arzobispo, Quebrada Molinos, Rio Callejas, and La Sirena streams or drainage channels. There are four officially designated wetlands and approximately 175 different parks and water bodies within the watershed. In all, 3 wetlands, 5 parks, and 2 green areas were selected for sampling the sub-watershed (Table 1).

**Figure 1.** The El Salitre urban sub-watershed in Bogota, Colombia, and its socioeconomic strata and ten sample sites. **Figure 1.** The El Salitre urban sub-watershed in Bogota, Colombia, and its socioeconomic strata and ten sample sites.

**Table 1.** Ten different sites characterizing three different green area types in the urban sub-watershed of El Salitre, Bogota Colombia. **Table 1.** Ten different sites characterizing three different green area types in the urban sub-watershed of El Salitre, Bogota Colombia.


The sub-watershed also encompasses all the different sub-neighborhood level socioeconomic strata that characterize Bogota. Bogota is divided into six different designated socioeconomic strata, that were designed to subsidize utility payments and infrastructure based on resident's average income, and thus are a measure of a residential zone´s income status; socioeconomic strata 1 being the lowest income and 6 the highest. These strata are correlated with green space cover and subsequent ecosystem service provision and benefits [38]. Bogota has a high population and building density and as such, the sub-watershed poses several socio-political and environmental realties typical of medium income Latin American cities. For example, sewage pollution discharges into the wetlands and streams in the forest reserve are common [39]. Urbanized areas near wetlands also experience frequent flooding, and informal settlements—both high and low income—are sporadically being established in the foothills and are characterized by high impervious surfaces and inadequate waste management [39].

Air and water pollution concentrations are also high along transportation land uses and stream channels. Streams, as previously mentioned, are channelized and made impervious to deal with excess stormwater and effluents [37,38]. Specific neighborhoods in the study sub-watershed such as Engativá and Suba are characterized by high rates of criminal activity [27,40]. Thus, given the complexity of sampling in densely populated areas with disparate socioeconomic realities and access and safety issues, we were not able to use other standardized methods for selecting urban sites that are frequently used in places such a Europe [41]. Instead, we selected 10 different and representative sites based on safety and access and we use these to represent the sub-watershed´s different socioeconomic strata and land uses (Table 1).

#### *2.2. Survey Instrument*

We used a semi-structured, in-person survey consisting of 18 different questions that assessed people´s perception and value for different urban benefits and costs as well as respondent's demographic and socioeconomic backgrounds (Appendix A). Questions were a combination of closed and open-ended items. In the survey, the first part of the questionnaire was about socioeconomic strata, gender, age, and education level. In a second section, we measured people´s awareness about the watershed's ecology in terms of their ability to recognize key ecological information by asking 4 questions about: Ecological health, different species, the existence of established wetlands, and an extensive forest reserve to the east of the city (Figure 1). Accordingly, employees of the Jardin Botanico de Bogota and students from the Universidad del Rosario surveyed people's perception towards climate change and their Willingness to Invest to conserve and restore the ten different green areas and wetlands we used in the study. In all, we surveyed 500 different people, or 50 respondents per site. Approximately 75% of the people who were approached participated in taking the survey and signed an informed consent form.

Based on [1,4,12,16,19,20], we analyzed 8 different benefits and 8 costs that have been reported to influence people´s perception and values regarding urban green and nature in cities. We also include crime-related costs [40] and poverty alleviation–income generating benefits [14] that are not accounted for in ecosystem service typologies [16,18]; but were important to the citizenry. We have found from previous experience that survey respondents in this study area do not distinguish among cognitively complex and technically difficult processes regularly used in ES frameworks such as "ecological functions", "ecosystem services and disservices", and "economic benefits". Rather, they simply recognize them as "benefits and costs". Thus, we also include crime related ED and poverty alleviation– income generating benefits that are not accounted for in typologies developed in high income countries such as those associated with the "ecosystem service cascade" [16]. Thus, we emphasize that the more scientific and technical terms ES and ED were posed as "benefits and costs" in the instrument to better communicate with respondents. However, in the following methods, results, and discussion sections, they are presented as ES, ED, and NCP to better contextualize and discuss relative to other relevant literature and studies.

#### *2.3. Statistical and Econometric Analysis*

Survey responses were in the form of dichotomous questions and Likert scales that were used to statistically characterize the survey population and their responses using two approaches (Appendix A; [15]). First, we summarized respondent´s socioeconomic strata, gender, age, and education level. Graphical analyses were used to identify trends and patterns in responses towards benefits and costs. Then an ordinary least squares (OLS) regression with robust standard errors: 1. Explored the variables that can influence perception towards different benefits and costs, and 2. identified variables for a subsequent analysis using a more predictive model. Following the work of [42], the following regression model (Equation (1)) accounted for the social–cultural dimensions of benefits (Bij):

$$Benefits\_{\rm ij} = \beta\_0 + \beta\_1 EA\_{\rm i} + \beta\_2 SS\_{\rm i} + \beta\_3 AE\_{\rm i} \ + \beta\_k X\_{\rm i} + \varepsilon\_{\rm i} \tag{1}$$

where *Bene f itsij* corresponds to the number of benefits identified by each individual surveyed in three categories: Provision, environmental, and cultural. This variable was modelled according to three types of sites: Parks, wetlands, and green areas. The independent variable *EA<sup>i</sup>* was the environmental awareness of each individual; *SS<sup>i</sup>* is the sense of security; *AE<sup>i</sup>* is a dichotomic variable that takes the value of 1 when the individual has a university degree, and 0 when the individual has a lower degree than a university degree; *Xi* is a 3 by 1 vector of control variables. This vector includes the following variables: Age, a dichotomous variable if the individual is from Bogotá, and another dichotomous variable if the individual is aware of climate change.

Second, we used survey responses and most of the variables from our OLS model in a logistic regression to econometrically assess the effects of Weak Governance (Weak\_governance) on respondent's Unwillingness to Invest (UTI) using Equation (2). Per Colombian program evaluation standards [31], a response of not willing to invest (i.e., UTI) included the following reasons for not doing so: 1. Perception of corruption or that funds will not be used appropriately, 2. conservation of green areas and wetlands is already paid for in taxes, 3. the respondents already pay too much tax, and 4. it is the government´s responsibility to conserve green areas. We recoded people´s Unwillingness to Invest as the dependent variable UTI = 1; conversely, UTI = 0 if people were Willing to Invest.

$$ProbLTI = \beta\_0 + \beta\_1 \text{ Weak\\_Govername} + \beta\_k X + \varepsilon\_i \tag{2}$$

Thus, based on [31] and [34], the Weak\_governance variable in Equation (2) was 1 if there was a perception of weak governance and 0 otherwise. The X in Equation (1) is a vector representing the socioeconomic variables that were used as controls. We used Gender = 1 for female, and Age was a categorical variable. Strata were recorded according to respondent´s socioeconomic strata (1, 2, . . . .6). In order to avoid perfect collinearity with the intercept of the model, stratum 1 was the omitted variable, as was Salitre if the respondent was from this locality and the city of Bogotá. Five of the 500 respondents did not respond to the UTI question, therefore we used 495 responses for this analysis. Logistic regression estimates were reported using Odds Ratios. Both regression models and all statistical analyses were done using the Stata Version 12 software.

#### **3. Results**

#### *3.1. Socioeconomic Characteristics*

The majority of the respondents (68%) were between 18–45 years in age, and 55% were male (Table 2). About 32% had a university level education, and only 2.4% had post-graduate studies. Fifty % were in the middle-income strata (Strata 3 and 4), while 20% were in the lower income strata (Strata 1 and 2).


**Table 2.** Socioeconomic characteristics of respondents in the El Salitre sub-watershed in Bogota, Colombia.

N, Number; Std. Dev., Standard Deviation.

#### *3.2. Perceptions of Benefits and Costs*

We found that air purification was the most frequently identified benefit as opposed to water regulation and quality (Table 3). Most notably, flooding regulation was the least identified benefit in all three wetlands. In parks and green areas, air purification was the most identified benefit, but respondents did identify provisioning benefits in parks, however, similar to wetlands, flood regulation and water quality were the least mentioned in both parks and green areas (Table 3).

Overall respondents identified 11 different costs in the watershed (Table 4.). Two of the wetlands, Tibabuyes and Córdoba wetland, and two parks, Montereserva and Parque Nacional, had the most costs identified. Respondents in the Cordoba and Tibabuyes wetlands, for example, reported crime and lack of maintenance and drug use. The Las Delicias Riparian area, the Botanical Garden of Bogotá, and the Nogal Park were the areas with least amount of costs reported. Overall, drug use was the main cost reported in parks. Since crime is a frequently reported problem or ecosystem disservice reported in other international literature [1,4,22], we here forth focus on this specific cost in subsequent analyses. The Cordoba (70%) and Santa Maria del Lago (94%) wetlands were reported as the safest places—in regards to crime—as opposed to the Tibabuyes wetland, which was the most insecure, as only 8% of respondents considered it safe (Figure 2).

It appears that respondent's perceptions regarding costs from urban ecosystems do affect their identification of benefits, and thus there appears to be a trade-off in the respondent's sense of wellbeing when they feel unsafe relative to the benefits they perceive. In general, the areas identified as safest were those that had the greatest number of benefits identified. Conversely, in sites that were the least secure, respondents identified the least number of benefits in wetlands, parks, and green areas (Figure 2 and Table 3).

*Land* **2021**, *10*, 14

**Table 3.** Perception towards benefits in 10 different green areas and wetlands in the El Salitre sub-watershed. Note: We integrate both the ecosystem services and nature's contribution to people (NCP) metaphors to better represent Bogota, Colombia's context and what citizens value from ecosystems and nature.


*Land* **2021**, *10*, 14

**Table 4.** Perception towards costs in 10 different green areas and wetlands in the El Salitre sub-watershed. Note: We integrate both the ecosystem disservices and problems from nature metaphors to better represent Bogota, Colombia's context and what citizens least value from ecosystems and nature.


*Land* **2021**, *10*, x FOR PEER REVIEW 11 of 22

**Figure 2.** Number of responses towards the perception of levels of a cost in the form of high crime (Unsafe) and low crime (Safe) in 10 different green areas and wetlands in the El Salitre sub-watershed in Bogotá, Colombia. **Figure 2.** Number of responses towards the perception of levels of a cost in the form of high crime (Unsafe) and low crime (Safe) in 10 different green areas and wetlands in the El Salitre sub-watershed in Bogotá, Colombia.

#### It appears that respondent's perceptions regarding costs from urban ecosystems do affect their identification of benefits, and thus there appears to be a trade-off in the re-*3.3. Factors Influencing Perceptions towards Benefits*

spondent's sense of wellbeing when they feel unsafe relative to the benefits they perceive. In general, the areas identified as safest were those that had the greatest number of benefits identified. Conversely, in sites that were the least secure, respondents identified the least number of benefits in wetlands, parks, and green areas (Figure 2 and Table 3). *3.3. Factors Influencing Perceptions towards Benefits*  Our OLS model shows that in general, environmental awareness coincided with a recognition of a greater number of environmental and cultural benefits (Table 5). Those with advanced degrees and that felt a greater sense of security, or lack of crime, also identified a greater number of environmental and cultural benefits. There was however no relationship between being born in Bogotá and the ability to identify benefits in the subwatershed. In terms of respondents surveyed in parks, those with greater levels of educa-Our OLS model shows that in general, environmental awareness coincided with a recognition of a greater number of environmental and cultural benefits (Table 5). Those with advanced degrees and that felt a greater sense of security, or lack of crime, also identified a greater number of environmental and cultural benefits. There was however no relationship between being born in Bogotá and the ability to identify benefits in the sub-watershed. In terms of respondents surveyed in parks, those with greater levels of education identified a statistically significant greater number of different environmental benefits. In wetlands, respondents: With more education, born in Bogota, and with more awareness about the local environment and climate change effects identified a greater number of environmental and cultural benefits. However, of those surveyed, respondents greater than 60 years old were those that identified the greatest number of environmental benefits (Table 5).

#### tion identified a statistically significant greater number of different environmental bene-*3.4. Factors Influencing the Conservation of Bogota*´*s Green Areas and Wetlands*

fits. In wetlands, respondents: With more education, born in Bogota, and with more awareness about the local environment and climate change effects identified a greater number of environmental and cultural benefits. However, of those surveyed, respondents greater than 60 years old were those that identified the greatest number of environmental benefits (Table 5). Overall, 97% of respondents do consider that conserving the watershed's wetlands and natural areas would improve the wellbeing of people living in their proximity. Fortyseven % felt that air quality improvement was the main benefit, followed by health and wellbeing (27%) and recreational activities (16%). However, when subsequently asked their WTI for an additional fee in their monthly utility bill to "protect and restore Bogotá's natural areas", 57% responded positively while 43% responded no. When asked why they were not willing to invest, 17% said that they already pay taxes and that this is the government´s responsibility, and an additional 16% said that they would not invest because of misuse of funds (i.e., corruption). However, of those that were WTI, 16% was because of improvement in wellbeing and protection of biodiversity (11%).

**Table 5.** Ordinary least squares regression model for socioeconomic factors that influence the environmental, cultural, and provision benefits identified in the El Salitre watershed (Robust standard errors in parenthesis) \*\*\* p < 0.01, \*\* p < 0.05, \* p < 0.1.


<sup>a</sup> The environmental awareness variable consisted of 3 questions: Can you identify 3 trees, palms, or plants in this place? Are you aware of the *Reserva Forestal Protectora Bosque Oriental de Bogotá* (the adjacent large extensive forest reserve to the east of the city)?; and Can you name wetlands that are located in Bogota? (Appendix A).

#### *3.5. The Role of Governance and Unwillingness to Invest for Ecosystem Services*

We found that WGOV was positively related and significant at all levels to a respondent´s UTI. According to the Odds Ratio, the chance of UTI for conservation was 31 times greater if the respondent perceived WGOV as opposed to strong governance (Table 6). When accounting for other socioeconomic variables, Odds Ratios show that if the respondent perceives WGOV, the UTI for conservation is 38 times greater than when perceiving strong governance (Table 7). The model shows that the control variables are not significant, however, WGOVC was very robust. Gender, age, and being born in Bogota were not significant, and the only significant related variables were for respondents in Strata 2 (upper lower income). That is, the Odds of UTI in strata 2 is 3.1, while for strata 6 (highest income) it is only 0.7.

**Table 6.** Logistic regression <sup>a</sup> and Odds Ratio of the effects of weak governance (WGOV) on people's Unwillingness to invest (UTI) for urban ecosystem benefits.


<sup>a</sup> Number of observations = 495; Log likelihood = <sup>−</sup>208.44138; LR chi2(1) = 258.53; Prob > chi2 = 0.0000; Pseudo R2 = 0.3828.


**Table 7.** Logistic regression <sup>a</sup> of the effect of weak governance (WGOV) on people's Unwillingness to Invest (UTI) controlling for gender, age, socio-economic strata, and residence.

<sup>a</sup> Number of observations = 495; Logistic Regression chi2(10) = 267.09; Prob > chi2 = 0.0000; Pseudo R2 = 0.3954; Log likelihood = −204.16118.

#### **4. Discussion**

Below we will discuss and interpret our findings relative to the relevant literature; thus we will use the term "benefit" and "cost" [1] as synonymous with ecosystem service and disservices, respectively. Later we will discuss the relevance of the NCP framework to our analysis [16,18]. Overall, our findings are similar to those of many other studies in that cultural and environmental benefits were the most identified by respondents, specifically, air quality, aesthetics, well-being, and recreation [43]. Ecosystem service studies in more rural contexts in middle and low-income countries have found that people focus on provisioning ecosystem services or benefits as defined in this study [14,44]. In contrast, in our study these were the least reported. Other studies in natural areas and wetlands in Colombia have also reported that people primarily identify regulation and cultural ecosystem services [45]. However, we do note that water regulation and purification were the least reported benefits in the sub-watershed as opposed to air quality regulation, which was the most frequently reported ES in the study. Shade, as opposed to other studies, was also not a top benefit [6]; but "biodiversity" was also highly valued. Interestingly, we note that these two are considered "ecological structure or functions" in the "ecosystem service cascade" framework—not benefits per se [3,4]. Interestingly, Bogotá's economic activities and topographic, high elevation, and precipitation characteristics, do not make air quality and temperature regulation issues as pressing as other Latin American cities; however, the city suffers regularly from floods and stormwater problems [38].

Overall, respondents from lower socio-economic strata perceived fewer benefits than those from higher income strata. Accordingly, one would surmise that these respondents spend less time in Bogota's green areas, but Scopelliti, M. el al. [15] found that it was low and high socioeconomic strata residents that spent the least time in Bogota´s urban parks. Regardless, our weak governance results seem to indicate that lower income respondents do not feel that they are, or should, participate in the decision-making processes. Our results also show that socioeconomics does play a role in the perception towards benefits. Some specific relationships between socioeconomic factors and the identification of benefits have been reported in [46] and [42].

Although income and education are related, there is an obvious relationship between education and environmental awareness, particularly in regards to the hydrological functions. Allendorf, T. D. et al. [47] found that education level does indeed affect how people perceive ecosystem services. Our results were similar; where people with the highest

level of education perceived more benefits than those without. One of the most insightful findings was the relationship between "wellbeing" and ecological structure-function-form in that the better maintained green areas were also those that were "safest" in terms of crime and where the majority of benefits were identified. Similarly, the majority of respondents were aware that there would be a loss in their wellbeing if these green areas were lost to land use change. Other research in Bogota has shown that public areas with increased tree-shrub-palm density and heights as well as tree plantings were related to lower incidences of crime and greater provision of benefits [19,38].

Based on Colombian program evaluation criteria [31] for principles and performance outcomes for good governance [34], our survey and modelling found that the perception of governance regarding public expenditures was playing an influential role in the WTI for benefits. Particularly, perceived weak governance was statistically related to people's UTI in conserving green areas. This finding suggests that transparency, performance, and perceived corruption of government institutions can and will influence buy in and the value citizens place on the benefits from urban ecosystems [33,34]. Furthermore, the effect of governance on the UTI for benefits was not homogeneous across all socio-economic strata. Notably, respondents in Stratum 2 identified a weakness in governance, and this affected their subsequent odds of not investing for conservation–benefits related initiatives; this was on average three times greater than individuals from higher socio-economic strata. Although income and education were related [48], there is an obvious relationship between education and environmental awareness in particular to the hydrological functions and other co-benefits [13,49].

The perception of weak or strong governance on watershed and ecosystem management, conservation, and urban ecosystem services—or benefits as defined in this study has been previously studied by [21,23,26,28,35]. Based on this literature and our findings, one of the main contributions of this study is that we have identified an influence of weak governance (i.e., lack of transparency, perceived corruption, and poor government performance) on how society values the urban green space benefits from Neotropical urban green areas and watersheds. Such information is key for improved governance, effective conservation, and sustainable provision of benefits to society [24,50].

Our literature review shows how governance is a complex metaphor, and that it has many definitions and is used in the context of urban ES and biodiversity studies; yet few studies have actually attempted to measure it and how it can influence urban benefits-costs, biodiversity, NCP or Nature-based Solutions [24,29]. Thus, to provide for a measure of governance, our study measured governance as consisting of: Transparency, corruption, and government performance. Our measure also incorporated aspects of Launay G.C. et al. [31] and Lockwood, M.'s [34] definitions of good governance as encompassing: Legitimacy, transparency, accountability, inclusiveness, fairness, connectivity, and resilience. Accordingly, we found that our corruption and transparency variables can be used as proxies for perceived corruption, and that funds intended for green area conservation might not be used appropriately as perceived by respondents. Similarly, our tax payment variables accounted for legitimacy, accountability, and government performance (i.e., trust). As such, we found that although residents pay taxes, many respondents are seeing fewer direct benefits (Table 6). Additional variables regarding the government´s responsibility for maintaining green areas accounted for the lack of inclusiveness, fairness, and overall transparency (Table 6). We found that even though respondents knew that the public areas they used and pay taxes for—and subsequently received benefits from them—they indicated a lack of confidence and poor government performance that inevitably affected their response.

We recognize that our use of "socio-economic and ecological processes", "ES/ED", and "benefits and costs" does not match the conventional ES typology and framework. Additionally, we note that we did not randomly sample individual sites in the watershed and that our sample size could have been greater. There will also be bias in our results because the surveyor did not randomly survey individuals or specific places in each site. Similarly, concepts such as governance and costs as pointed out by our literature review

are complex metaphors to define and measure. Environmental values, resource conflicts, power relationships, green infrastructure types, and structure will also affect how people perceive benefits-cost bundles [20]; these were not studied though. However, given security and access issues and our review of the relevant literature, we feel that our approach and modelling results do provide initial insights into the role of perception and the role of governance on urban green area benefits and costs in a major Latin America city.

Future research could study the perceptions towards benefits and costs and the effect of other field and in situ cognitive measurements of green space and forest structure and composition. As indicated by a reviewer, the opportunity exists for also including other questions as explanatory variables in our models for better understanding citizen opinions of these functions such as perceptions regarding costs, difference dimension of governance, or other environmental and social capital factors and how they affect the valuation of benefits. Indeed, other biophysical factors such as size and density of green areas per neighborhood could also affect human well-being [2]. Similarly, using other methods from environmental psychology and experimental economics could also offer other causal insights as well. That said, the approach used in our study to measure benefits and effects of weak governance and institutional transparency can be used in adopting and improving ecosystem service-governance frameworks such as those proposed by [13,51], and [24] to Latin American socio-ecological systems and their contexts [20]. Implications can also be made regarding the relevance and application of "Nature-Based Solutions" or a more culturally and context relevant approach such as the recently proposed "NCP"; a particularly promising metaphor (Table 3) [18].

Indeed, management and governance of the wetlands and green areas in Bogotá as a public resource does require accounting for such multiple and complex issues and language [3,50]. Our findings, for example, also show the importance of focusing environmental education efforts and topics on certain demographic groups. Although people were knowledgeable about the environment, biodiversity, and nature and its benefits, there was a notable lack of awareness regarding the important hydrological benefits provided by the watershed's green areas. As such, there is an opportunity to educate the public about the existence and benefits of the positive ecological processes provided by wetlands and parks for the protection of lives and property in Bogotá. Finally, based on our study area and findings, in order to get buy in from society in conservation efforts, it is essential that public institutions improve their perceived lack of transparency an performance [31,33–35].

Sarkki, S. et al. [51] proposed different types of "governance services" for different arenas (i.e., policy, markets, society, science) as a way to understand ecosystem service dynamics and incorporate them into management and planning frameworks. Falk, T. et al. [36] also proposed that governance types need to be adapted according to specific benefit types and institutions. Therefore, key to linking well-being with governance and policy uptake is to identify a given society´s perceptions and values concerning the benefits and costs from green areas [24,50]. However, much of this ecosystem services-governance literature presents concepts, conceptual frameworks, and case studies primarily from countries in the Global North and wildland, rural ecosystem-based contexts [16,24,33]. However, our findings add to the emerging ecosystem services, NCP, and governance literature in that we: Addressed socio-ecological dynamics for low-middle income contexts, measured governance using evaluation metrics, and informed how policy processes and incentives can affect citizen´s UTI in green space and wetland conservation.

#### **5. Conclusions**

Our findings provide very basic and useful, yet overlooked, information and guidelines for managers, educators, policy makers, and local planners. In particular, urban park and wetland users can identify the various benefits from urban nature. However, as in the case of water regulation, information needs to be targeted and context-specific. That is, in surveyed wetlands, people perceived that air quality was more important than water regulation. Despite the fact that flooding and water quality problems are much more

acute problems in the sub-watershed than air quality issues. Additionally, we found that conventional ES typologies and frameworks developed in high income countries need to be adjusted and adapted in order to match the realities on the Global South. The NCP or Nature-Based Solutions approaches as such provide fertile grounds for future use and application in places such as Latin America cities.

Similarly, people's perception of crime and the overall lack of maintenance and infrastructure influenced the overall benefit's they identified from green areas. This was particularly evident with respondents from lower socio-economic neighborhoods. So, people with different education and socioeconomic levels do weigh the tradeoffs of personal security and perceived lack of governance against the conservation and provision benefits of and from these areas in different ways. In particular, costs such as crime and litter did affect them, but detrimental ecosystem structures and their negative functions are easily addressed in a relatively low-cost manner and can effectively influence how people perceive these urban benefits. Thus, it is important for planners to consider safety and maintenance of wetlands and parks because basic simple management, maintenance, and planning activities can play a role in people´s perception and probably in attitudes and investment of public resources towards those areas.

Accordingly, conservation and effective management of wetlands, parks, and green areas is key, and citizens can indeed identify the benefits versus the costs of conserving them. In order to provide long-term benefits from urban ecosystems, effective governance processes and environmental education efforts based on the premise that humans are integral parts of social–ecological systems is key. The perception of good governance is regularly considered important in this link, but the perceived lack of transparency will be a limiting factor in people´s buy in and willingness to invest in and maintain the necessary ecological structure that provides the most benefits and minimizes costs. Accordingly, lack of governance processes and trust towards the institutions developing and implementing them will affect the effectiveness of existing planning and management goals.

The benefits and costs of urban green areas—be they referred to as ecological processes, biodiversity, ES, ED, NCPs, or nature-based solutions, are key in improving the social, economic, and environmental well-being of citizens; regardless of the metaphor used. Participatory management and planning of urban green areas requires information on how the different segments of society perceive both the benefits and costs of urban socioecosystem functions. Thus, effective institutional capacities and transparent state and non-state centered processes require information on what the different actors perceive about not only ES/ED, but of the governance and policy processes inherent in delivering the supply of benefits—and the mitigation of costs—from wetlands and green areas. Indeed, where good governance is absent, "bottom up" initiatives by citizens are one means to move towards improving the well-being of people living in urban and peri-urban areas of the Global South; regardless of what metaphors scientists from the Global North desire to use to describe these benefits and costs.

**Author Contributions:** Conceptualization, A.P.-G. and F.J.E.; methodology, F.J.E. and A.P.-G.; formal analysis, A.P.-G., F.C., and F.J.E.; writing—original draft preparation, A.P.-G. and F.J.E.; writing review and editing, F.J.E., A.P.-G., and F.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Data Availability Statement:** The data presented in this study are available on request from A.P.-G. and the corresponding author. The data are not publicly available due to personal data and contact information collected as part of the survey.

**Acknowledgments:** We thank the Jardin Botánico de Bogotá- José Celestino Mutis for funding and leading this project particularly Carlos Fonseca, José Lopez, Catalina Lopera, and Maribel Vasquez for their assistance and coordination of field crews. We are also grateful to the Universidad del Rosario´s Biology Program's undergraduate Socio-ecological Systems class for their valuable contribution to this work. In particular, we thank Mari Paula Otero, Sara Pedraza, Andrea Aragon, Daniel A Quevedo, and Nubia Vazquez.

#### **Conflicts of Interest:** The authors declare no conflict of interest.

#### **Appendix A**

**Table A1.** Table listing response variables, units, and data types for the survey instrument presented in Supplementary Material A. Note: Only analyzed responses and variables are presented.



#### **Table A1.** *Cont.*


**Table A1.** *Cont.*

#### **References**


### *Review* **Which Traits Influence Bird Survival in the City? A Review**

**Swaroop Patankar 1,\*, Ravi Jambhekar <sup>1</sup> , Kulbhushansingh Ramesh Suryawanshi 2,3 and Harini Nagendra <sup>1</sup>**


**\*** Correspondence: swaroop.patankar@apu.edu.in

**Abstract:** Urbanization poses a major threat to biodiversity worldwide. We focused on birds as a well-studied taxon of interest, in order to review literature on traits that influence responses to urbanization. We review 226 papers that were published between 1979 and 2020, and aggregate information on five major groups of traits that have been widely studied: ecological traits, life history, physiology, behavior and genetic traits. Some robust findings on trait changes in individual species as well as bird communities emerge. A lack of specific food and shelter resources has led to the urban bird community being dominated by generalist species, while specialist species show decline. Urbanized birds differ in the behavioral traits, showing an increase in song frequency and amplitude, and bolder behavior, as compared to rural populations of the same species. Differential food resources and predatory pressure results in changes in life history traits, including prolonged breeding duration, and increases in clutch and brood size to compensate for lower survival. Other species-specific changes include changes in hormonal state, body state, and genetic differences from rural populations. We identify gaps in research, with a paucity of studies in tropical cities and a need for greater examination of traits that influence persistence and success in native vs. introduced populations.

**Keywords:** urbanization; birds; ecosystem services; survival; adaptations; traits

#### **1. Introduction**

Today, urbanization presents a major threat to biodiversity [1,2]. By 2050, 68 percent of the world's population will live in urban areas [3]. As urban settlements increase, the landscape undergoes drastic change from its pristine state [4]. However, ecologically speaking, urban areas are highly modified and fragmented habitats, in the form of several managed and unmanaged urban green spaces, like public and private garden, nature reserves within the city, vacant plots, to name a few, which are capable of providing resources to a small number of highly adaptable species of fauna [2,4–6]. Not only resident, but several migratory, species make use of this urban habitat [7]. The urban avian community is composed of introduced and invasive species and highly adaptable native species [8,9], although Aronson et al. [8] observed that the community is dominated by locally adapted species, with only five percent non-native species. The urban greenspace along with the biodiversity it harbors, forms a unique ecosystem within the human dominated landscapes, capable of providing several ecosystem services to the cities [2]. Ecosystem services are the services that are beneficial to humans as a result of naturally occurring processes [10], which render them all the more important in human dominated landscapes, like cities.

Birds, which are some of the most successful urban adapters, provide a range of ecosystem services. Birds, in general, are capable of significantly affecting ecosystem processes, due to their specific characters, like flight capability, high metabolic demand, which leads to tolerance to discontinuous food sources; and, flock formation, which significantly affects

**Citation:** Patankar, S.; Jambhekar, R.; Suryawanshi, K.R.; Nagendra, H. Which Traits Influence Bird Survival in the City? A Review. *Land* **2021**, *10*, 92. https://doi.org/10.3390/ land10020092

Academic Editors: Alessio Russo and Giuseppe T. Cirella Received: 26 November 2020 Accepted: 19 January 2021 Published: 20 January 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

ecosystems processes, like nutrient cycling [10]. The urban bird community structure also acts as an indicator of the structure and functionality of urban areas as habitats [11]. In this study, it was found that habitat specialists, like woodpeckers and hole-nesting birds, occurred in the peripheral areas of the city, indicating healthier vegetation cover, while habitat generalists increased near the city center and residential areas with less vegetation cover.

Birds have been found to provide all four types of ecosystem services that were mentioned in the UN millennium ecosystem assessment, namely, regulatory, provisioning, supporting, and cultural [10]. Urban birds provide regulatory services by acting as pest control agents when they feed on disease causing insects, prey on rodent population, and scavenge on garbage; provisioning services by acting as seed dispersers when they ingest fruits, which helps in plant regeneration; and, supporting services by acting as nutrient recyclers via their excretory products [12,13]. However, urban birds perhaps play the most crucial role in providing various cultural services. One of the most important services rendered by urban birds is to act as a connecting link between the natural environment and the increasingly nature deprived urban denizens [7]. Birds in residential neighborhoods in cities are generally valued for their color and songs, for providing mental and physical wellbeing, as indicators of seasonal change, for education, and for giving sense of familiarity, by the residents [7,14]. Birds are also an inspiration for art, recreational activities, like birdwatching and wildlife gardening [10]. In India, it is a tradition of grain merchants to give a small portion of their goods to granivorous birds, like house sparrows (*Passer domesticus*), as an offering for prosperity in business. In the city of Delhi in India, it is a common practice of offering meat to scavengers, like black kites (*Milvus migrans*) as religious practice, due to which the black kite population dynamics in the city is significantly affected [15].

It is abundantly clear that the conservation of these ecologically important fauna in urban landscapes is crucial. Many cities are now experimenting with the management of urban green spaces for conservation and, there have been numerous studies on the effect of such management interventions on bird ecosystem services in cities [13]. However, for such management practices to be entirely successful, it is also important to understand the uniqueness of birds who call this urban habitat their home. One is then compelled to ask what characteristics sets apart the birds able to adapt to this unique habitat from those who disappear from it? It would be counter-intuitive to the purpose of conservation if such measures are taken without understanding the changes in "traits" of urban birds.

Studies on trait changes have grown in recent years, as researchers begin to focus on the study of urban areas as modified habitats. It has been suggested that studying the traits of urban biodiversity could be a more effective approach for preserving the ecosystem functions and services in urban areas, ss such data provide authentic and useful information to urban planners [12]. Birds comprise the taxon that is perhaps the best studied in cities. Birds constitute especially useful model species for studying trait changes, as they respond to changes rapidly, are of interest to naturalists and the public at large, are easy to monitor, and they show measurable changes. They have hence been studied widely in the urban context [16,17].

McKinney et al. [1] conducted the last comprehensive review assessing diverse trait changes that were observed in urban birds. In general, only certain species, which are characterized by specific traits or combinations of traits, seem to be more capable of coping with the environmental alterations that are imposed by urbanization [18]. This capability might differ according to season, geographic region, or city structure [9], but such species of urban utilizers can tolerate a wider range of environmental conditions [19] and they appear to exhibit similar characteristics globally [20,21]. The research on bird adaptations to urban habitat has since expanded considerably. Many researchers have carried out reviews and meta-analyses of specific trait changes, including behavioral traits [22,23], community traits [21], and physiological changes [24]. However, there is a need for an updated comprehensive review that collates and synthesizes existing information.

This paper reviews research studies on traits that influence the survival and response of birds to urbanization, based on a literature review of research that was conducted between 1979 and 2020, identifying the state of current knowledge, highlighting key knowledge gaps, and identifying geographic and species-specific disparities in research that require specific focus. The specific aim of this study was to synthesize the information available on studies when comparing urban and rural birds while taking a trait-based approach. Finally, we highlight the gaps in knowledge and pinpoint future directions for research.

#### **2. Materials and Methods**

We listed and categorized the traits that are described in birds referring to the review paper by McKinney [1] and making additions of our own. The traits were selected with the knowledge that they were essential for basic survival and reproductive success of birds. To begin this review, we conducted an intensive literature search for each trait, using Google Scholar during August 2019, based on combinations of the following keywords: "urban", "birds", "urbanization", "impacts", "traits", "changes", "effects", "behavioral", "physiological", "functional", "diversity", "global", "avifauna", "song", "life history", "nesting", "foraging", "generalist", and "specialist". Each publication that resulted from this search was reviewed to determine whether it met the criteria for inclusion. The basic criterion was that the study had to be either a comparative field study or an experimental study looking at effects of urbanization in an urban-rural gradient on bird communities or a single bird species. The literature was searched by its importance and relevance to the key words used. Review papers and experimental studies were included as a part of this study. The reviewed papers were grouped into five broad trait groups: ecological traits, which included traits pertaining to ecological niche and community interactions; life history traits, which included traits that are related to reproductive success, breeding cycles, and overall survival; physiological traits, which were related to the physiological, endocrine, and morphological changes in the birds in urban areas; behavioral traits, which were the changes in important behaviors, like singing, fear responses, innovative behavior, to name a few; and finally, genetic traits, which were the trait changes in the genetic structure of urban birds (for complete list, refer Supplementary Materials Table S1). Each paper was read and categorized based on the methodology used, the results, and interpretations of the study. Knowledge gaps and scope for further research were documented.

#### **3. Results**

A total of 226 publications were finally included for review (Supplementary Materials Table S2). The earliest paper that we found was published in 1979. The field has grown rapidly since then, with research on several different traits (Figure 1; Table 1). The interdisciplinary nature of the topic has led to an expansion in the number of journals publishing urban ecological research (Supplementary Materials Figure S1). Behavioral Ecology published the most papers on trait adaptations in urban birds, followed by Urban Ecosystems, PLoS ONE, and Scientific Reports (Supplementary Materials Figure S1). Many of the trait changes have been studied on large bird communities at the regional or global scale. Song birds and water birds are well studied, and most of our understanding of impact of urbanization comes from these guilds of birds (Table 2). Additionally, some bird species such as Eurasian blackbird (*Turdus merula*) are widely represented in the literature as compared to others. Studies from temperate countries dominate the literature, with only a few studies from the tropics (Figure 2).

**Figure 1.** Number of research papers on urban bird traits related to urbanization from 1979 to 2020.




**Table 1.** *Cont*.

**Table 2.** Bird families represented in the literature studying urbanization induced trait changes. Bird community studies comprise of global reviews or analysis of global datasets, while individual family studies comprise of local datasets and experimental studies.


**Figure 2.** Distribution of research studies on urban bird traits across the world. Studies carried out at state or province level included multiple cities which were not specified in the publication.

#### *3.1. Ecological Traits*

#### 3.1.1. Bird Diversity and Abundance

An overall decrease in diversity from rural to urban areas [25–27] as well as an increase in abundance of only a small subset of species are some of the most important ecological effects of urbanization on birds. One study observed a decreased overall abundance of birds in urban areas [28]. Species richness also shows a decreasing trend with an increase in urbanization, a pattern observed globally [29,30]. A study encompassing several cities in Europe observed that urban bird communities also showed lower evolutionary distinctiveness than rural communities [31]. A global review observed that, despite the loss of forest dependent or native species in urban areas, the functional diversity remained the same [32].

The species richness and density of seasonally migrating species also reduces with an increase in built infrastructure [33,34]. Many birds, such as Eurasian blackbird and house sparrow, show a loss in migratory behavior, as there are enough food resources available in urban areas to support them through the winter months. Such a trend may eventually lead to reduced richness in urban areas [35]. Birds with specific dietary requirements may also avoid migrating to cities because of a lack of adequate food resources. For example, insectivorous birds might find difficulty in finding insects in cities, thus reducing their urban population [35,36]. Studies also speculate the indirect effects of urbanization on resident vs. migrant bird dynamics. Resident species may occupy good quality nesting sites in cites before migrants arrive, thus driving migrants away from urban areas by competitive exclusion [37].

#### 3.1.2. Generalism—Specialism

Specialist species are more likely to be negatively affected by change than generalists [38–40]. Devictor et al. [41] found that generalists, which use multiple habitats in the landscape matrix, are less affected by habitat fragmentation than specialists, which

are dependent on one or a few habitat types. Generalists should benefit from disturbed landscapes, as there will be reduction in competition from specialists, who do well in stable environments and, hence, will be negatively affected by a degradation in landscape [42,43]. Generalist species usually have large niche breadths, lay multiple clutches, and have broad diets, which makes them more successful in cities [39]. This indicates that, to understand whether a bird can cope with urbanization, we need to consider the effects of multiple traits together.

Whether a species is a generalist or a specialist is largely due to the ability of these birds to adapt to feeding and nesting preferences, as described further below.

#### 3.1.3. Diet Breadth

Diet breadth is one of the most important traits affected by urbanization [44,45]. Bird species that feed on fruits and grains tend to increase in numbers in urbanized areas as compared to insectivorous species [37,46,47]. This might be because cities have a substantial proportion of fruiting trees [48]. Similarly, a review on urban raptors suggested that urban areas are typically inhabited by raptors that are feeding on forest dwelling birds, due to a prevalence of large trees in cities, but open-area raptors feeding on grassland species do not generally inhabit urban areas [49]. Raptors feeding on rodents and scavenging raptors also show similar foraging, depending on the availability of suitable prey or carrion [50–52].

In many countries, there is a culture of putting out bird feeders, supplementing bird diets with seeds, nuts, and grains [53]. Granivorous birds benefit from this and, hence, do well in urbanized areas [27,37]. Callaghan et al. [39] observe that insectivorous and granivorous birds avoid urban areas, a phenomenon that requires further investigation in order to assess whether it is specific to countries where feeding birds is not a popular activity.

Kark et al. [44] report that, in downtown areas, most of the birds were omnivores, especially in temperate countries. Similarly, urban bird composition in Santiago, Chile, predominantly consisted of omnivorous and granivorous species [47]. Omnivorous species, like Eurasian blackbird, great tit (*Parus major*), and house sparrow, are commonly studied in urban avian ecology research (Figure 3). Again, omnivore birds are likely to feed on food scraps, discarded food items and, thus, seem to be possibly making use of the food resources that are discarded by humans. Apart from food preferences, urbanization can negatively affect birds exhibiting solitary feeding behavior [39]. Many birds show subtle changes in foraging behavior in order to adjust to the novel foraging sites. Ground foraging and insectivorous birds forage differentially in suburban remnant patches vs. continuous vegetation [54].

**Figure 3.** Most commonly studied bird species for urbanization induced trait changes.

#### 3.1.4. Nesting Sites

The utilization of nesting sites is an important factor determining the success of bird species [45]. One of the most consistent effects of urbanization is on ground-nesting birds, whose abundance consistently decreased across most of the studies [16,55]. Small sized ground nesters are most impacted by urbanization in Australia [56]. Birds that nest on high trees and in tree cavities have a better chance of survival in cities [37,57]. Studies speculate that urbanization does not necessarily increase the availability of cavity nesting sites. However, cavity nesters might be less prone to predation, because of their nesting habit, hence surviving better in cities [37]. Alternatively, cavity nesting birds might be using artificial nesting sites, such as nest boxes provided in cities. Cities with good tree cover will benefit birds that nest on trees, as there will not be a scarcity of nesting sites.

Birds that are more adaptable and use a variety of nesting strategies like making use of man-made structures, are more likely to do better in urban areas as compared to birds with specialized nesting preferences [58–60]. Adaptive nesting strategy also ensures better productivity, as is seen in the urban peregrine Falcon (*Falco peregrinus*), as many artificial structures provide better protection against predators or the elements [61]. Consequently, species that are adapted to urban conditions show higher abundance in urbanized areas [8,59,62]. Other birds, such as open-cup nesters, which require trees and shrubs to support their nests, are negatively associated with urbanized areas [59].

#### *3.2. Life History Traits*

Life history traits, such as clutch size and brood success, have a considerable positive impact on bird populations in urban areas [37]. Many urban species show an increase in the clutch size and brood size [63]. The increase in number of eggs and chicks helps these birds to overcome the losses that occurred during predation or the effects of urbanization such as mortality caused due to collision with cars or windows [37,61]. Urban birds tend to lay eggs earlier than their rural counterparts [64–68]. This might be because of the improved resource availability in cities. There are exceptions; Chamberlain et al. [69] found that, even though results vary from species to species, most urban bird populations are characterized by slightly greater annual productivity and lower nestling weight. However, certain species do not show such a pattern. For example, Marini et al. [70] find that clutch size does not differ in mountain chickadees (*Poecile gambeli*) as one moves along the urban-rural gradient in North America. Similarly, in magpies (*Pica pica*), a European species, the clutch size does not vary as one moves across the rural to urban gradient [71]. Brood size and nestlings per nesting attempt did not show a consistent pattern of differences between urban and non-urban areas [69]. Some raptor species also fledged fewer offspring in urban areas when there was a lack of prey or excessive human disturbance [68].

#### *3.3. Physiological Traits*

#### 3.3.1. Body Mass, Size, and Plumage Coloration

Birds may produce large broods in urban areas, but the condition (average body size, morphological features) of offspring is poor, because there is a high chance of survival, even for the low-quality offspring [72,73]. The change in diet preferences might be associated with higher survival rates, but poor body condition. Birds have ample resources available throughout the year in the city, which is perhaps the reason they do not accumulate more body fat. Another possible reason is that temperatures in cities are higher due to urban heat island effects; hence, birds have smaller sizes: as theory predicts that as temperatures drop, body size increases [73]. Adverse ecological effects may also constrain the body size or condition of offspring [73]. Nestlings in urban habitats are fed less amount of food, or lower quality food, and they reach a lower body mass [74,75]. However, the urban area-smaller mass relation is not observed in all urban birds. A study on silver gulls (*Larus novaehollandiae*) in Tasmania found that adult male gulls in urban areas had greater body mass than adult male gulls in rural areas [76]. Perhaps omnivorous species show an opposite trend in terms of body mass due to the consumption of a wide variety of foods.

Liker et al. [75] found that house sparrows were larger in rural areas as compared to urbanized areas. Sparrows in the Budapest city center were more than 5% lighter than sparrows at the least urbanized locations, and the leanness of urban birds was detectable, even when they compared differently urbanized habitats with similar utilization [75,77].

Although the literature on body size and mass of urban birds is comprehensive, research is only now emerging on changes in plumage coloration in urban birds. A recent study across three cities in Argentina showed that the amount of built area negatively affected the color diversity of bird communities. Hence, the bird community in the city was predominantly composed of grey colored species [78]. Urbanization selects for birds with similar colors, primarily those matching the surrounding habitat. Because plumage coloration is an important trait, not only for the reproductive success of birds, but also as a camouflage to avoid detection, it is important to be studied on a larger spatial scale.

#### 3.3.2. Brain Size

Birds and mammals with relatively larger brain size may be associated with the ability to invade novel habitats [79,80]. Callaghan et al. [39] hypothesize that birds with large brain size might be favored in cities and, hence, such birds should be successful in urban environments. Theory predicts that larger brains might be advantageous to individuals in dealing with altered environments and it might help in innovative behavior and learning [81]. Larger brain size implies that individuals might be more able to explore novel environments and food resources, helping such birds adapt to city life [5]. However, experimental studies suggest that there is a lot of variation in brain size and success in urban environments [82,83]. More work is required in order to definitively declare whether brain size is actually related to success in urban environments.

#### 3.3.3. Stress Response Physiology

Urban birds are exposed to a variety of stressors, like traffic noise [84,85], artificial light pollution [86,87], uneven food distribution, and chemical pollution [85,88]. Stress response to such disturbances is indicated by the level of plasma corticosterone hormone (CORT) secretion [24,84,89–91]. Many studies have revealed changes in the baseline and induced corticosterone levels in birds in response to urban stresses [85,88–90]. The Eurasian blackbird female shows an increased corticosterone secretion in response to artificial light exposure [86], even though Partecke et al. [88] had observed an overall decrease in corticosterone secretion in urban blackbirds. Urban birds also show reduced corticosterone secretion in noisy environments when compared to rural populations, as is displayed by song sparrows (*Melospiza melodia*) [84] and house wrens (*Troglodytes aedon*) [85]. Reduced corticosterone in urban birds is associated with low protein diets [85]. The decrease in CORT secretion in species that have colonized urban areas for a long time could be due to habituation to these stressors [84,86,89]. When male song sparrows from different parts of city were compared for CORT levels, they did not show any difference, which further indicates that these urban song sparrows might be adapted to urban stressors [84]. Bonier [24] reviewed the various endocrine trait changes in urban birds and found no consistent pattern in stress hormone change in all urban species. Even within the populations, the differences fluctuated according to the age and life history stage.

Elevated levels of baseline corticosterone may have a considerable effect on other behavioral and physiological functions. Brain Arginine Vasotocin immunoreactivity, which is associated with various functions, like territoriality and social behavior, differs in response to changed plasma corticosterone in urban curve-billed thrashers (*Toxostoma curvirostre*) [92].

#### 3.3.4. Reproductive Physiology

Living in urban areas influences reproduction in birds [24,93–96]. A global analysis of passerine species found that sexually dichromatic species were less likely to occur in urban areas [97].

Urban populations of Abert's towhees (*Melozone aberti*) are found to have greater plasma luteinizing hormone (hereafter plasma LH) than rural populations [67]. This leads to urban birds developing gonads earlier, starting breeding earlier, and having a prolonged breeding season than rural birds [64,66,67,98–100]. Having a prolonged breeding season might help in the production of more broods and, thus, might be an important trait to have in urban areas to successfully colonize them. Such earlier gonadal development is also prominent in resident rather than migratory birds, as observed in the males of urban Eurasian blackbirds [101] and dark-eyed junkos (*Junco hyemalis*) [101].

Partecke et al. [64] suggest phenotypic plasticity in response to several new conditions, like artificial lights, in urban areas to be the primary reason for this change. Birds living in temperate regions are especially dependent on day length and duration of natural light for their reproductive development [95,98,99]. The presence of artificial light in the city habitat plays a major role in the earlier growth of gonads in male birds [66,87,98,99,102,103]. However, low levels of artificial light inhibit the secretion of plasma LH in male western scrub jays (*Aphelocoma californica*) [91,95]. Apart from artificial light, differential food availability could also affect the pattern of plasma LH physiology [69,91].

Factors, like the vegetation structure, replacement of native plants by exotic species, habitat fragmentation, predatory pressure, and food availability, influence the life history traits of urban birds [69,104]. The reason for lower clutch size in urban compared nonurban areas could be because of lower availability of high quality or specialized food in urban areas, especially during chick development [105]. Such deficiency in good quality food could also lead to increased competition between conspecifics during breeding season, affecting clutch size [69].

Such changes in reproductive physiology could affect life history traits, like fitness levels and nesting success of urban birds [98,99]. A prolonged breeding season could also be favored by urban birds, leading to fewer birds migrating for breeding [64,101].

#### 3.3.5. Immune and Inflammatory Responses, Oxidative Stress Response

Physiological responses to various stressors in cities contribute to oxidative stress in urban birds [106,107]. Increased oxidative stress exposes birds to different types of diseases and organ degeneration [107]. A comparative study of blood and liver transcriptomes for these stress responses revealed that most of the genes for this stress response were expressed in a higher amount in urban birds [108]. An increase in blood antioxidant levels helps urban birds to tolerate such stress [106]. Successful urban colonizers use also genetic and epigenetic mechanisms, DNA methylation, and histone changes to cope with oxidative stress [107]. Urban Eurasian blackbirds developed lower oxidative stress when compared to rural populations, indicating an adaptation to high stress levels [109].

Physiological traits also closely influence behavioral traits: hormone secretion is associated with reproductive behavior, and brain size with innovation.

#### *3.4. Behavioral Traits*

#### 3.4.1. Song Structure

One of the major characteristics of urban areas is the increase in low frequency noise levels, such as from traffic [110,111]. Birds in urban areas are impacted by noise in the low frequency range, as it carries over longer distances [111,112]. Low frequency anthropogenic noise tends to mask bird songs, which leads to poor song transmission, and, ultimately, poor reproductive success. Perhaps one of the most widely documented phenomena in behavioral trait changes in birds in response to urbanization is the modification of song and call structure to avoid such masking (Figure 4).

There are thought to be two mechanisms by which birds alter their song structure. One school of thought suggests that birds sing at higher frequencies in areas with high anthropogenic noise levels, as shown by studies on several species of song birds across different continents (e.g., [113–117]). In fact, high frequency songs are one of the selective forces for species to occupy urban habitats [118]. However, this mechanism might not

always be effective for reproductive success [119–122]. White-crowned sparrow (*Zonotrichia leucophrys*) change song frequency and bandwidth, which leads to a reduction of vocal performance, which is deleterious for mate attraction and territory defense [120,122].

**Figure 4.** Proportion of studies in each decade from 1970 to 2020 on different trait changes due to urbanization.

Some birds also increase the amplitude of their songs, a phenomenon called "Lombard effect", in order to be heard above the city noises [111,123–126]. Great tits and Eurasian blackbirds are classic examples exhibiting this phenomenon [111]. Changes in bandwidth, trill rate, number of song syllables, and time spent singing have been documented in some birds, for effective song transmission [121,122,127–129]. Urban European robins (*Erithacus rubecula*) sing nocturnally in order to avoid song masking [35,110]. The alarm call structure is also modified due to masking. Urban silvereyes (*Zosterops lateralis*) had lower average, maximum, and minimum frequencies than rural birds [130]. Silvereyes also showed decreased syllable rate in Australia [131].

Apart from traffic noise, reflective structures, vegetation density, ambient temperature, and temporal changes in noise levels due to human activities also affect song communication in birds [132,133]. Male house finches (*Haemorhous mexicanus*) in an urban park in California sing at higher frequencies in areas with higher pedestrian traffic [134]. In the case of the great tit, this phenomenon is attributed to either large scale evolutionary or ontogenetic shift or a local scale song learning from neighboring males [112,113]. Morphological changes, like change in bill structure, due to differential food type in cities, could also change song structure [135].

Urban noise and artificial light levels affect the dawn chorus of urban bird populations [136,137]. Males of four out of five songbird species residing near street lights started singing earlier in the day. This increased their extra pair copulation success, but led to females selecting unsuitable mates [138]. Other studies found that more than artificial light, anthropogenic noise is responsible for temporal shift in the dawn chorus of the study species [117,136,137].

#### 3.4.2. Boldness and Tolerance to Human Presence

Urban habitats have a constant presence of humans and vehicles, altered refuge patches, and differential predator composition [139–144]. Flight initiation distance (FID) is a standard measure for estimating the boldness and tolerance of birds to potential threats in urban areas [23]. Urban birds are observed to be bolder and more tolerant of human and vehicular approach, as they exhibit shorter FIDs [145–152].

A shorter FID reduces the cost associated with flight, and it can help birds exploit novel food sources. Several species of gulls have shown shorter FID in the proximity of human food sources [153–155]. In a study on 39 urbanized species of birds in Europe, urban birds had shorter FIDs than rural counterparts. [156]. This study also showed that the urban bird community had a larger variance in FID when compared to rural bird communities, but this variance decreased with increase in time since urbanization. This means that most of the birds adapted to the threats in urban areas as the time since colonization increased.

Along with FID, urban birds have also adapted to the predation threat of feral animals, like cats and dogs. Urban Eurasian coots (*Fulica atra*) portrayed the same amount of vigilance in the presence of domestic dogs as their natural predators [139].

Behavioral plasticity, which is the inherent ability of an organism to change in response to external stimuli, is one of the main characteristics exhibited by birds who are capable of changing their fear responses. This is thought to be an important adaptation to possess in urban areas. [157–159]. However, it has been argued that habituation induced change is not the reason for the higher tolerance of humans in urban areas. Those individuals who already had a bold personality in their natural habitat were able to colonize urban areas, while others were unsuccessful [82].

#### 3.4.3. Neophobic and Innovative Behavior

Urban areas provide novel types of food resources in the form of artificial feeding or garbage dumps [153,160–162]. Novel urban food sources also come with new types of risks in the form of feral cats and dogs [160,163–165]. Not all native birds have the ability to exploit such sources of food—it seems that bird species with innovative capability and bold personality have an increased capacity to thrive [152,166–168]. Several species of gulls exhibit a great ability to exploit human provided food, for example, by adjusting their foraging time according to peak human activity timing, like school breaks or waste center opening time [169]. Not just foraging innovation, but certain urban species, like Indian house crows (*Corvus splendens*), also show innovative nesting behavior after nesting failure during breeding season [170].

Successful urban colonization requires a balance between neophilia and neophobia [162]. Urban great tits are more tolerant towards a novel object that is placed near their feeders than rural individuals [165]. However, two different studies on house sparrows in Hungary and mountain chikadees in Reno, USA indicated no reduction in object neophobia in urban populations [171,172]. Griffin et al. [162], in a review, suggested that neophilia/neophobia and boldness might be species specific. Corvid species were more neophobic towards novel objects than non-corvid species [173].

Exposure to pollutants and inferior quality food during chick development might also affect the ability to exploit novel food sources as well as learning from parents and conspecifics [162,167]. Research pin pointing the factors influencing the ability to exploit novel urban resources is required.

The ability to innovate different foraging techniques is crucial for successful urban colonization by birds [160,168,174]. The rate of innovation seems to be stronger during early invasion of novel urban areas [5]. The rate of innovativeness also seems to predict the risk–taking ability of the species [168]. The rate of innovation has also been linked to brain size in some urban birds, which also assists in successful urban colonization [175]. Innovative foraging also leads to changes in dominance hierarchy, behavioral strategies that are based on human movement, and introduces new types of competitions [176].

#### 3.4.4. Aggression

Aggressive behavior can be displayed towards competitors [176–179], can be food related [180], due to exposure to chemical pollutants [181], or during nest defense [182]. Urban great tits were more aggressive towards competitors, but they exhibited inconsistent reaction towards a simulated competition when compared to their rural counterparts [179].

Urban great tits also showed greater distress behavior when threatened [183]. In another study on northern mockingbird (*Mimus polyglottos*), urban birds that were exposed to higher amounts of lead were more aggressive towards simulated competition [181]. In Eurasian coot populations residing in the same urban area, older and more established populations were consistently more territorially aggressive than recently colonized population [184]. Urban sparrowhawks (*Accipiter nisus*) showed more aggressive nest defense than rural sparrowhawks [182]. These changes might not be just behavioral adaptations, but a consequence of micro-evolution over the years in these birds causing changes in the behavior. However, differences in territorial aggression in urban birds appears to be species and situation specific. The species that show increased aggressive behavior in urban areas also generally exhibit bolder personality [155,176].

#### *3.5. Genetic Traits*

Although phenotypic trait changes in birds in response to urbanization have been extensively studied, solid evidence for genetic basis for such phenotypes is limited. Studies have focused on finding out the genetic modifications behind observed physiological trait changes like inflammatory and oxidative stress response, morphological trait changes, like change in wing structure, behavioral changes, like risk assessment, migration and urban invasion by certain functional groups [107]. The urban populations of great tits in Europe had elevated gene expression for inflammatory, oxidative stress, and detoxification responses [185]. Similar results were obtained for urban blue tits (*Parus caeruleus*) [186].

Urban Eurasian blackbirds have undergone genetic divergence at a locus coding for risk avoidance [187]. Human induced changes in habitat, along with various stressors, like the presence of novel predators, traffic noise, and pollutants, have led to accelerated changes in genotype in urban populations when compared to rural populations, with the potential to create genetic divergence between urban and non-urban populations [185]. However, an attempt to study the differences in overall genetic composition of Eurasian blackbirds yielded negative results [188]. This suggests that genetic differences between urban and rural populations have only occurred in selected genes, based on adaptive requirements. Urban blackbirds diverged from their rural populations at a single loci coding for risk avoidance [187]. However, there is still little evidence for urbanizationinduced micro-evolution.

#### **4. Discussion**

Some bird traits are beneficial for their survival in cities, while others could be harmful. This review demonstrates that the impact of urbanization on birds is immense: and yet, our understanding of it is still poor. It is evident that studying one trait might not give a complete picture of how urbanization might affect birds or populations, but looking at a combination of traits would provide more insights.

Behavioral trait changes are dependent on plasticity, individual personalities of the bird populations, and, at least for a few species, the development of separate cognitive skills that are specific to urban needs [22,170]. In particular, as our review demonstrates, behavioral trait changes in urban birds are often a combination of two or more trait changes. Such correlated changes create behavioral syndromes in urban birds [171]. An example of such behavioral syndromes is the occurrence of increased aggression in birds with bolder personalities [176].

The consequences of trait change have not yet been studied in detail, and they require attention. Urban birds could incur energetic and reproductive costs due to changed corticosterone levels or increased aggression in urban areas. The ability to establish a successful breeding population in novel environments also depends on the population size and selection pressure [22]. Earlier and prolonged breeding seasons could have negative effects on reproductive health of urban birds, especially females. Therefore, even though, in the short term, birds might be adapting to urbanization by producing more broods and laying more eggs, we need to understand whether these birds will be successful at surviving in cities in the long term. Additionally, it is important to understand the reasons behind some birds showing a reduction in clutch and brood size in urban areas. Long term data collection is needed for monitoring the population of birds inhabiting the cities. Popular citizen science initiatives can help to answer some of these questions.

In the context of physiological and morphological trait changes, the literature suggests changes in stress hormone levels and reproductive hormone levels. The reason for the lack of consistent pattern in the differences in hormone levels in urban and non-urban populations could be due to the selection of physiologically plastic species in urban areas, which affects the life-history traits and ultimate density of the populations. This could mean potential extinction of species that are currently residing in urban areas, but are not able to adjust their physiology to the novel environment [24]. However, the effect of such differences in hormone levels on the overall fitness of the bird species that are successful in changing their endocrine traits has not yet been investigated in detail.

Trait changes in response to urbanization have the potential for creating genetic divergence between urban and rural populations of a species. The most important trait change contributing to genetic divergence is the change in reproductive behavior. A combination of different traits, like singing behavior, timing of reproduction, and nesting success, play a role in the reproductive pattern of birds. Urban areas modify these traits. Song birds possess high phenotypic plasticity and they have changed song structure in response to urban noise. Trait changes, coupled with isolation due to habitat fragmentation further leads to disconnect between urban and rural populations, leading to differential trait development in both populations. There is already evidence to suggest changes in genetic makeup at certain loci in urban and rural populations. Geographical isolation, coupled with high phenotypic plasticity, has a potential for further genetic divergence in urban birds. Large scale spatial and temporal studies, investigating such microevolution due to urbanization, could help in predicting the course of genetic divergence of urban bird populations in the future. Studying such urbanization induced genetic trait changes could help not only in conserving biodiversity in cities, but could also help to answer some of the basic questions in evolutionary ecology and also help in conserving the ecosystem services in cities [185].

There is a large gap in our knowledge regarding the effects of urbanization on birds in tropics, despite the fact that tropics support many more bird species and they are growing rapidly in terms of urbanization [55]. Future research in this area could also differentiate between introduced species and native species, in order to understand whether the traits discussed in this review contribute to the success of introduced species.

A lack of information regarding how urbanization will affect avifauna in urban tropics can be a major impeding factor while designing conservation strategies to protect the biodiversity in these ever-growing cities. Moreover, a study on southeast Asian cities found that, the wealthier the cities get, the richer they become in terms of urban greenspaces and natural aesthetics [189]. This could lead to potential habitat generation in growing cities, further affecting the bird traits.

Studies have started to emerge on the effect of urbanization on the traits of diurnal and nocturnal raptors in the last decade. Studies on urban raptors mainly focus on reproductive success, foraging pattern, and aggression in urban areas. Studies on top predatory bird species are essential while making management decisions, as these top predators might be responsible for keeping invasive faunal populations in check. For example, an increase in rodent populations on islands has led to the extinction of several island dwelling birds and other fauna [190]. Similar effects might affect bird populations in urban areas if proper management decisions are not taken at an appropriate time. Further, certain species are poorly represented in the research. Most of the studies that focus on species specific trait changes focus only on a few common species, such as great tits, Eurasian blackbirds, and house sparrows. Behavioral and physiological studies carried out on a couple of species might skew the literature in concluding effects of urbanization, either positive or negative and making generalizations. Caution should be taken that there is a lot of inter-species and intra-species variation and we need more studies looking at a variety of species and a combination of traits. For example, gulls seem to show extraordinary innovative ability around humans when compared to other urban birds. There is further scope to generate species specific databases in order to understand the effects of urbanization on diverse bird species and communities.

Urban areas provide a unique habitat in which to study community dynamics of birds. For example, in urban parks where there is a surge in activity during weekends, community composition of birds in these parks might be affected [78]. This could be very important, as, even though these are areas with good green cover, they might not be suitable nesting sites as park visitors might cause disturbance to nesting birds and might lead to abandoning the nest. On the other hand, these areas might be good areas to forage for fruits, seeds, and insects during the weekdays. An interesting hypothesis could be tested, looking at nesting success in the parks and outside the parks to actually see the effects of disturbance on bird communities and individual species.

#### **5. Conclusions**

The most significant trait changes that we identify have implications for urban avian diversity conservation, and they can be of use to park managers, citizen science groups, and urban planners. Omnivorous and cavity nesters have a better success in urban environments when compared to insectivores and ground nesting birds. Urban planners and park managers can maintain small patches of land that are enclosed to protect against common urban predators. such as feral dogs, cats, and rodents, in order to provide ground nesting birds that are especially endangered with refugia for roosting and nesting. Another important suggestion to bird enthusiasts and urban planners would be to include a variety of food items in bird feeders, as this might help birds with different diets to meet their nutrition requirements. Studies have shown that frugivores and granivores seem to do well in cities, as these birds feed on the seeds that are provided by people in bird feed. There has been evidence that, when artificial food is provided birds expand their ranges, thus having a positive effect on bird populations [78]. If dried insects and nuts are included in the food, it might help insectivorous birds in the city. If bigger cavity nests are provided for birds, like owls and other larger species, then these species might bounce back in good numbers in the cities. Additionally, maintaining patches of native vegetation in urban habitats might be a great solution for supporting not only the bird species, but also insects and small mammal communities that can serve as a prey base to the birds. Along with patches of native vegetation, it is also crucial to conserve the local water bodies in cities, as these act as refuges for several migratory birds and local waders [46,191]. In the Mediterranean, it was observed that the natural waterbodies were key habitat for several species of owls [192]. Hence, the health of the lakes, ponds, and rivers is crucial for the survival of many urban species.

Species specific studies and detailed knowledge of local bird populations can greatly help in effective management measures, as we find substantial, documented variation in how birds of specific species respond to the pressures of urbanization. We hope for the long- term monitoring of bird populations while using a combination of detailed scientific research and citizen science initiatives, as demonstrated in the papers reviewed here, can help to bridge gaps in knowledge and benefit the future survival of a diverse range of birds in urban environments. To conclude, using a trait-based approach will be useful for understanding the impacts of urbanization on bird species. Understanding the role of traits with an understanding of urban changes will be most useful. In particular, we stress the need for further research on the traits that influence bird survival in tropical cities, as well as on individual species. A meta-analyses kind of an approach encompassing multiple traits together was out of scope for this study, as enough information on each trait is still not available. Some traits have enough literature, others have hardly a couple of studies. However, this review could act as a baseline for further research on urban wildlife and its ecology.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/2073-445 X/10/2/92/s1, Figure S1: List of journals which published the (>1) articles reviewed in the current study; Table S1: All traits considered for selecting the literature were distributed under five broad trait groups. In total, 32 sub-traits were considered for this study. The broad description of these sub-traits is given below; Table S2: List of publications reviewed for this study.

**Author Contributions:** S.P.: Conceptualization, Methodology, Data Curation, Analysis, Writing— Original Draft Preparation, Reviewing and Editing. R.J.: Conceptualization, Methodology, Data Curation, Analysis, Writing—Original Draft Preparation, Reviewing and Editing. K.R.S.: Conceptualization, Supervision, Writing—Reviewing and Editing. H.N.: Conceptualization, Methodology, Supervision, Writing—Original Draft Preparation, Reviewing and Editing, Project administration. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors thank Azim Premji University, Bangalore for supporting this research. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


**Lorena Alves Carvalho Nascimento \* and Vivek Shandas**

Nohad A. Toulan School of Urban Studies and Planning, Portland State University, Portland, OR 97201, USA; vshandas@pdx.edu

**\*** Correspondence: lorena.nascimento@pcc.edu

**Abstract:** Municipalities worldwide are increasingly recognizing the importance of urban green spaces to mitigate climate change's extreme effects and improve residents' quality of life. Even with extensive earlier research examining the distribution of tree canopy in cities, we know little about human perceptions of urban forestry and related ecosystem services. This study aims to fill this gap by examining the variations in socioeconomic indicators and public perceptions by asking *how neighborhood trees and socioeconomic indicators mediate public perceptions of ecosystem services availability.* Using Portland, Oregon (USA) as our case study, we assessed socioeconomic indicators, land cover data, and survey responses about public perceptions of neighborhood trees. Based on over 2500 survey responses, the results indicated a significant correlation among tree canopy, resident income, and sense of ownership for urban forestry. We further identified the extent to which the absence of trees amplifies environmental injustices and challenges for engaging communities with landscape management. The results suggested that Portland residents are aware of tree maintenance challenges, and the inclusion of cultural ecosystem services can better address existing environmental injustices. Our assessment of open-ended statements suggested the importance of conducting public outreach to identify specific priorities for a community-based approach to urban forestry.

**Keywords:** urban forestry; cultural ecosystem services; public survey; tree maintenance

#### **1. Introduction**

By 2050, the United Nations suggests that the world human population will near 10 billion, with most living in urban centers. In the United States (US), eighty percent of the population already live in urban areas, which corresponds to only 3% of national land [1]. The fast pace of urbanization and landscape change caused by humans are the major factors for transforming forests, urban and otherwise [2]. Some have argued that the transformation of urban landscapes brings an 'extinction of experience' with nature [3], which impacts the well-being, public health and empathy for natural features. The management of urban areas requires the consideration of multiple land-use possibilities for conservation of built or natural environments. Roads, buildings, urban renewal, green infrastructure and new developments compete for limited urban space. This fact requires municipalities to use strategic approaches to manage urban growth with civic services, including sewer, roadways and other gray infrastructures. Often with priories of gray infrastructure, the available locations for tree canopy is reduced and existing tree canopy is removed—a phenomenon that has been well documented across the US [4,5].

Several scholars have argued that urban tree canopy can be better managed by characterizing ecosystem services, which describes the benefits that trees and other natural landscape features provide to humans. For urban trees and tree canopy, these are often described as improvement of air quality, reduction of heat, filtering and infiltration of stormwater and a host of cultural attributes that improve the overall quality of life for residents [6,7]. Ecosystem services, in the form of tree canopy, come in three essential categories: (a) those in parks, schools, open spaces and other natural areas; (b) those on

**Citation:** Alves Carvalho Nascimento, L.; Shandas, V. Integrating Diverse Perspectives for Managing Neighborhood Trees and Urban Ecosystem Services in Portland, OR (US). *Land* **2021**, *10*, 48. https://doi.org/10.3390/land1001 0048

Received: 30 November 2020 Accepted: 31 December 2020 Published: 7 January 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

private lands, owned by somebody other than a public agency; (c) those on streets and other public rights-of-way.

Municipal governments generally manage the urban tree canopy through a distributed model that embeds tree specialists in different public agencies or through a central division that works with other agencies. Few municipalities, if any, explicitly examine the host of ecosystem services that constitute the urban forest. We argue that urban ecosystem services as a management approach can help situate the urban forest within broader and potentially more inclusive management of natural features. The rationale behind our approach for ecosystem services lies in these three points: (a) they offer a cost-effective and functionally-based solution to major challenges facing urban areas, including rising temperatures, air pollution and flooding; (b) when properly applied, ecosystem services can support a more equitable distribution of canopy, which is currently highly centered on wealthy and white communities; (c) the consideration of ecosystem services can improve human-nature relationships, create a sense of ownership of places and provide stewardship and community engagement opportunities. Together these functions of urban trees and forests compel their careful management, though the extent to which communities view or even understand these ecosystems services remains unclear.

This study examines the role of community perspectives concerning urban canopy management by assessing the relationship between the quantity of neighborhood tree canopy, public perceptions of ecosystem services and socioeconomic indicators to support urban environmental planning. Many studies have found a positive correlation between tree canopy and residential income [8–10]. However, few examine the extent to which public opinion about planting priorities, maintenance challenges and the expectations for urban ecosystem services can be central to decision-making processes. We posit that engaging the public in myriad and creative ways in urban forestry efforts is increasingly essential. Planting and maintaining trees can promote a connection between residents and urban environmental services according to each neighborhood's needs, regarding socioeconomic, cultural and historical aspects.

#### *Background*

The use of urban ecosystem services (UES) in describing trees and forests is a relatively new idea [6,7]. Four categories of UES classify the services provided by the maintenance, preservation and conservation of urban forestry. First, supporting UES contributes to nutrient cycling and soil formation through tree debris and habitat for decomposers. Second, provisioning UES for urban foraging of food and natural medicine [11]. Third, regulating UES, as local climate resilience that prevents urban heat islands [12], air quality that mitigates respiratory problems [13] and stormwater catchment that controls flood and water flow [14]. Fourth, cultural UES bring socio-ecological values through selfactualization, esteem and belonging [7], connection with biodiversity and personalized ecology [15]. The literature of ecosystem services [16] is gaining popularity, with research that includes public perception evaluations and how the ecosystem services adjust to reflect community identity.

UES relies on urban forestry and green infrastructure management, including public participation in strategic planning to recognize multiple ecological needs in diverse contexts. People's involvement in managing urban forests is often heralded as necessary for ensuring a just and equitable distribution of ecosystem services. However, communities' engagement may be mediated by intersectional factors that are often not considered in planning decisions [7]. For example, older adults and children are more vulnerable to respiratory diseases and may be highly sensitive to degraded air quality; black communities have been historically excluded from desirable green areas [17]; queer identities struggle to be accepted in heteronormative nature spaces [18]; low-income residents have less canopy access [8].

Urban forestry scholars have already acknowledged the link between socioeconomic factors and access to ecosystem services in the municipalities. McPhearson et al. [19] called

attention to incorporating UES into urban planning since cities globally are rapidly increasing in population. The persistent need for environmental justice and climate resilience created a framework for using ecosystem services as planning metrics. Wilkerson et al. [7] developed an urban sociological framework to explain the intersectionality between UES planning and social demands because the variation of socioeconomic factors impacted the accessibility to green spaces. Empirical studies that measured urban accessibility based on socioeconomic indicators found geographic mismatches within vulnerable groups for the balance (demand/flow ratio) of ecosystem services of climate regulation [12], food supply and recreation [20].

While these earlier studies call out distributional inequities, we need to establish programs and policies to ensure that historically underserved communities are at the center of urban forestry programs. We argue that urban forest planning needs to acknowledge and incorporate voices from diverse communities when managing distributional equity. Moreover, we need to find effective and practical approaches for hearing voices from communities, especially about their perceptions of trees and the factors that mediate the level of saliency for expanding tree canopy in historically disinvested neighborhoods. Since the fields of forestry and more recently urban forestry, have been mainly heteronormative, white and male [18], advancing a call for expanding the participatory process to include opinions that have not traditionally heard is instrumental to ensuring canopy equity in cities.

To provide a basis for our argument, we evaluated the presence of trees and public perceptions of ecosystem services through a community survey in Portland, Oregon (OR), US. The study aimed to understand what people expect about greening strategies, tree maintenance and tree planting priorities. We specifically asked, *how do neighborhood trees and socioeconomic indicators mediate the public perceptions of ecosystem services availability?* We addressed this question through integrative analysis, involving a survey, socioeconomic indicators and spatial analysis of neighborhoods in the study area. Portland has several advantages for a study of this kind, including an inequitable distribution of trees [10]; historically unserved areas that reflect racist planning policies [21]; and late incorporation as a city in the United States, leaving with its existing tracts of large trees, even today [22]. At the same time, Portland's regional culture seems to have an explicit appreciation for urban forestry, as evidenced by establishing the first Parks Commission in 1900 and green corridors West of Willamette River planned by the Olmsted Brothers in the early development of the city services [23].

#### **2. Materials and Methods**

#### *2.1. Study Area*

Located in the Pacific Northwest region of the United States, Portland bears the earliest and most preserved forest formations in the country [24]. Once called Silicon Forest [25], over the past 20 years, Portland attracts people looking for jobs in the tech industry and individuals seeking outdoor recreation and lifestyles. The physical geography has forest fragments in hilly areas to reduce the chance of landslides, as illustrated in Figure 1. Portland's canopy cover follows geological points of interest, like rivers, wetlands and elevated formations.

Most of the city's canopy is west of the Willamette River in the Northwest (NW) and Southwest (SW) zip code sectors (Figure 1). Portland's western sectors also contain the most topographical relief for which trees protect from erosion, landslides and riverbanks [26,27]. Western sectors of the study region had extensive early conservation policies by the Parks Commission, with the Olmsted Brothers' support. This landscape architecture firm promoted urban ecology practices, such as green corridors, large urban parks, wildlife habitat and biodiversity in the early 20th Century [23].

Across the Willamette River, the eastern zip code sectors have flattened surfaces containing fewer trees than the western sectors. The eastern sectors are North (N), Northeast (NE), Southeast (SE) and East (E). The eastern sectors have a larger proportion of

industrial and commercial areas and the largest percent of the city's population [22]. The Columbia River, the second largest river in the United States [28], surrounds North and East Portland. The high susceptibility to floods resulted in a 21-mile levee system created to allow urban development in areas along the Columbia River's riverbanks. Among the 654,741 people living in Portland [29], at least 25.6% live in the East sector [22], which is growing fast in terms of ethnic and income diversity. Still, Portland has a history of racist urban planning, redlining [30,31], gentrification [21,32,33] and late incorporation of eastern neighborhoods [22] that explains the separation between low-income communities and canopy abundance. lumbia River, the second largest river in the United States [28], surrounds North and East Portland. The high susceptibility to floods resulted in a 21-mile levee system created to allow urban development in areas along the Columbia River's riverbanks. Among the 654,741 people living in Portland [29], at least 25.6% live in the East sector [22], which is growing fast in terms of ethnic and income diversity. Still, Portland has a history of racist urban planning, redlining [30,31], gentrification [21,32,33] and late incorporation of eastern neighborhoods [22] that explains the separation between low-income communities and canopy abundance.

Across the Willamette River, the eastern zip code sectors have flattened surfaces containing fewer trees than the western sectors. The eastern sectors are North (N), Northeast (NE), Southeast (SE) and East (E). The eastern sectors have a larger proportion of industrial and commercial areas and the largest percent of the city's population [22]. The Co-

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**Figure 1.** Map of Portland, Oregon, USA, with canopy distribution over the six zip code sectors: Southwest (SW), Northwest (NW), North (N), Northeast (NE), East (E) and Southeast (SE) City of Portland [34]. Oregon Spatial Data Library [35], USGS [36]. **Figure 1.** Map of Portland, Oregon, USA, with canopy distribution over the six zip code sectors: Southwest (SW), Northwest (NW), North (N), Northeast (NE), East (E) and Southeast (SE) City of Portland [34]. Oregon Spatial Data Library [35], USGS [36].

#### *2.2. Research Design 2.2. Research Design*

We used a cross-sectional research design that applied satellite-derived measurements of the tree canopy cover, demographic analysis and assessments about the public perceptions of the urban forest. This study used three parameters that encompassed tree canopy measurements from the National Land Cover Database (NLCD), socioeconomic indicators from the US Census and a public survey about urban forestry perceptions applied in Portland. The aim was to assess the extent of the connection between people and UES following the level of satisfaction and accessibility to urban tree canopy [9]. By integrating the biophysical with survey responses, we argued that we were better able to describe how the presence or absence of neighborhood trees mediated differences in the perception of tree maintenance and tree ownership in the study area. Evaluation of public We used a cross-sectional research design that applied satellite-derived measurements of the tree canopy cover, demographic analysis and assessments about the public perceptions of the urban forest. This study used three parameters that encompassed tree canopy measurements from the National Land Cover Database (NLCD), socioeconomic indicators from the US Census and a public survey about urban forestry perceptions applied in Portland. The aim was to assess the extent of the connection between people and UES following the level of satisfaction and accessibility to urban tree canopy [9]. By integrating the biophysical with survey responses, we argued that we were better able to describe how the presence or absence of neighborhood trees mediated differences in the perception of tree maintenance and tree ownership in the study area. Evaluation of public perceptions can offer insights, perhaps a first step, to understand the extent to which urban forest management can better support communities in the maintenance, ownership and accessibility to trees among different socioeconomic groups.

#### 2.2.1. External Datasets for Tree Canopy Cover and Demographic Data

US Census data from 2017 estimates [29] regarding income, race and homeownership had two specific roles in this study. First, we wanted to note the fidelity of our survey sample. We compared the values of socioeconomic indicators from the survey and census. Second, we used census data as the parameters for socioeconomic indicators. The census data had higher representability and more complex data collection than the demographic questions from the survey. We aggregated the census data by zip code, following the delimitation of study areas from the survey.

The canopy cover percentage was obtained from the NLCD with 30 m × 30 m spatial resolution. The dataset informed the percentage of canopy per pixel [36,37]. On ArcGIS software, we used the Extract by Mask tool to mask Portland boundaries and the Tabulate Area tool to measure the canopy area per zip code. Equation (1) calculated the average canopy percentage by zip code. The shapefiles for zip code and neighborhood boundaries were from the Portland Maps web library [34]:

$$\text{Canopy cover} \left( \% \right) \, = \sum (\text{ZAi} \times \text{Ci}) / \text{area} \tag{1}$$

where ZA is the zip code area per canopy percentage, C is the percentage of tree canopy per pixel and area is the total zip code area.

#### 2.2.2. Survey Data for Public Perceptions of Urban Forestry

To explore the public perceptions of UES, we used the results of an online public survey conducted between May and July of 2017. Portland is known for the neighborhood bonding and strong connection that residents have with their vicinities [25]. Therefore, we used zip codes as the determinant scale and the unit of analysis. A total of 26 zip codes were large enough to have representative samples to assess patterns of responses and small enough to provide variations in our sample. We excluded zip codes from neighborhoods with less than fifteen answers for a better variability of answers and representation.

The survey had 26 questions that explored the views of Portlanders about the quality of the local urban forest, strategies for planting programs, possibilities for tree maintenance and a socioeconomic questionnaire [38]. For this study, we combined 12 relevant questions that addressed: (a) the sense of ownership of trees; (b) the sense of maintenance for trees in public spaces; (c) the perception of UES on strategies to increase urban forestry; (d) and socioeconomic indicators (Appendix A).

The first six questions of our study encompassed the perceptions of tree ownership and maintenance [Appendix A—Questions 1–6]. Three questions about tree ownership asked the participants about: (1) the importance of trees; (2) the satisfaction with the number of trees and (3) the satisfaction with trees' health [Appendix A, Questions 1–3]. Three questions about tree maintenance inquired about (1) the maintenance of existing trees in the right-of-way; (2) maintenance of trees in the right-of-way in low-income communities and (3) planting new trees in the right-of-way [Appendix A, questions 4–6]. The participants used a Likert scale ranging between 1 and 5 to inform how much they agree or disagree with the six sentences related to tree ownership and tree maintenance. Table 1 shows the range of Likert scale values, tree ownership and maintenance questions and multi-metric evaluation.

Instead of analyzing the six questions separately, we created two multi-metric indexes: Tree Ownership Satisfaction Index (TOSI) and Tree Maintenance Satisfaction Index (TMSI). TOSI combined the three questions about tree ownership and TMSI the three questions about tree maintenance. TOSI and TMSI also used a Likert scale and we calculated them by finding the average values of the three questions of each index, as displayed in Table 1. TOSI and TMSI resemble multi-metric indexes used in the biological assessment of watersheds [39,40].

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**Table 1.** Where Q is the question number, Tree Ownership Satisfaction Index (TOSI) is the tree ownership satisfaction index and Tree Maintenance Satisfaction Index (TMSI) is the tree maintenance satisfaction index.


One open-ended question asked the participants about municipality strategies to increase tree canopy [Appendix A, question 7]. After observing the responses, we coded repetitive values from the answers and created a typology based on UES and management challenges. Table 2 shows the coded values that translated the public concerns about ecosystem services, tree maintenance and financial concerns.

The last survey question about urban forestry asked if participants had trees on their property [Appendix A, question 8]. We measured the answers per zip code, informing the percentage of participants that had trees on their yards.

Four questions explored the socioeconomic characteristics of the participants [Appendix A, Questions 9–12]. We asked questions about the participants' race, income and zip code for the socioeconomic indicators. These indicators were traditional demographic parameters in other urban forestry and ecosystem services studies [8,10,12]. We also asked about housing ownership, as house tenure is an indicator of membership and active participation in urban environmental planning [41]. We compared the survey data's socioeconomic indicators to the census data to reinforce the survey sample's validity.

**Table 2.** Coded values from the open-ended question regarding strategies to increase tree canopy.


2.2.3. Survey Data for Public Perceptions of Urban Forestry

To integrate the analysis from the NLCD tree canopy, census and survey datasets, we developed a conceptual model that described the analytical steps for addressing our research aims (Figure 2). The conceptual model contained, at its core, the research question: *How do neighborhood trees and socioeconomic indicators mediate the public perceptions of available ecosystem services?* The conceptual model also integrated the datasets vis-a-vie specific questions that reference each of the three datasets we employed:


**Figure 2.** Flowchart with the research questions and research design.

To answer the first two questions, we performed the Pearson correlation test between the socioeconomic survey questions and Census data and between tree canopy data and Census data, as the variables were parametric. To answer the third question, we performed the Spearman correlation test between the tree canopy data and the survey urban forestry questions, as the variables were nonparametric. For both Pearson and Spearman correlation we considered the results that were significant with *p* < 0.05. For the urban forestry questions in the survey that used a Likert scale (Table 1), we performed Cronbach's alpha, which is a reliability test for the internal consistency of scaled questions and their variance. All statistical tests were performed with SPSS software v.26. Using the open-ended responses, we created a UES typology table (Table 2), which also served as additional data for evaluating and corroborating the statistical analysis.

#### **3. Results**

The survey for public perceptions of urban forestry and UES had 2548 valid answers from 26 zip codes within Portland. The survey responses ranged between 15 and 249 an-

swers per zip code [Appendix B, Figure A1; Appendix B, Table A1]. As a voluntary online survey distributed in community engagement platforms (municipal listserv, Nextdoor, social media channels, focus groups, public meetings), there was a high chance that the participants had previous interests in urban forestry and city planning. We obtained completed answers and discarded those who did not complete the survey.

In the following subsections, we will answer the specific research questions regarding the correlation between the variables of census data, survey data and tree canopy data. In the last subsection, we will summarize the core question "*how do neighborhood trees and socioeconomic indicators mediate the public perceptions of ecosystem services availability*?" using the open-ended statements and their associations with the statistical findings.

#### *3.1. Does the Variation of Socioeconomics in the Survey Provide a Good Representation of the Census Data?*

To answer this question, we compared the census data and survey's socioeconomic indicators, which were both collected in 2017 (Table 3). The correlation between survey answers and the number of households per zip code was moderately strong (R = 0.554) and significant (*p* < 0.01). This result suggested that the number of respondents reflects the total population size within the zip codes.

We found strong Pearson correlation values between the census and the survey for the variables of house ownership (R = 0.796; *p* < 0.01) and income (R = 0.922; *p* < 0.01). The percentage of house ownership was higher among the survey respondents (82.09%) than the values indicated by the census data (51.54%). We believed that our survey targeted participants aware of the local public budget [39], as property owners have more responsibility with taxes that support tree maintenance.

For the race variable, both data from the census and the survey showed that Portland has a majority white population in all zip codes. Due to this fact, we labeled all non-white races as people of color. People of color (POC) is a term commonly used in the US to describe a population that is not white. The correlation values between the census and survey data for the POC variable was moderate (R = 0.402, *p* < 0.05). The percentage between POC in the census (22.22%) and survey (23.29%) had similar values.

Overall, the results suggest that for the specific characteristics the survey contained a representative sample for the city as a whole, which provides support to address the remaining questions. Our survey had a consistent representation with the Census data, with significant values for population size, race, income and house ownership.


**Table 3.** Pearson correlation values between socioeconomic indicators from the survey and census.

\* Level of significance = 0.05; \*\* level of significance = 0.01.

#### *3.2. Is There a Relationship between Tree Canopy and Socioeconomic Indicators?*

Earlier research from several studies across the United States [6–8] and Portland [36] suggested that historically underserved communities are less likely to have immediate access to tree canopy. In contrast, white and wealthier populations have greater access, partly due to historical policies that segregated neighborhoods [38]. This study was no exception and corroborated previous findings. Using Equation (1), we observed that zip

codes in NW and SW had higher tree canopy than zip codes in the eastern sectors (E, N, NE, SE) of the Willamette River. NW and SW had respectively 42.5% and 37% of canopy cover and \$125,739 and \$100,696 of household incomes (Table 4). East had the lowest income (\$57,104) and 12.4% of average canopy. The values of household income were obtained from the census data.

**Table 4.** Average tree canopy and income within the zip codes sectors in the study area.


Pearson correlation values between tree canopy and census socioeconomic indicators for income, race and house ownership (Table 5). The strongest correlation across all the sociodemographic was between tree canopy and income (R = 0.625, *p* < 0.01). This result supported the findings observed in Figure 1 and Table 4, with a high percentage of canopy cover in affluent neighborhoods of West Portland, suggesting that people with higher income in Portland have more access to the urban tree canopy. The results for the correlation between tree canopy with house ownership (R = 0.206; *p* > 0.3) and race (R = −0.186; *p* > 0.3) did not have significant values. As such, we conclude that income is the only significant (and positively correlated) variable in relation to the amount of tree canopy for the study area, as found in other urban forestry studies that used Portland as a case study [10,38,42].

**Table 5.** Pearson correlation values between tree canopy and census socioeconomic indicators.


\*\* Level of significance = 0.01.

#### *3.3. Does the Presence of Trees Influence the Public Perception of UES?*

#### 3.3.1. TOSI and TMSI Indicators

We combined three questions to build the TOSI, regarding: (1) the satisfaction with the number of trees; (2) the good condition of trees and (3) the importance of trees. The TMSI combined three questions about: (4) the maintenance of street trees; (5) the maintenance of trees in low-income communities and (6) the planting of new trees. Table 6 shows Cronbach's alpha results for the questions that encompassed the indexes.

While the Cronbach's alpha value of 0.490 can increase to 0.612 by removing Question 2 of the TOSI and TMSI multi-metric, we maintained the question because only 78.63% of respondents addressed all six questions, while 8.70% respondents answered five questions, 6.98% answered four questions, 5.61% answered three questions and 0.08% answered two questions. While multi-metric methods (ecosystem services coding, Likert scale, TOSI, TMSI) are reduced by including additional questions, some of which may not be addressed, doing so also increases the diversity and reliability of responses. In addition, surveys about public perceptions of urban forestry are relatively limited and the development of such metrics and observations, we expect, can contribute to further comparative studies.


**Table 6.** Cronbach's alpha for the Likert scale questions of survey. **Questions Mean Std. Deviation**

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**Table 6.** Cronbach's alpha for the Likert scale questions of survey.

**Total Statistics Cronbach's Alpha = 0.490 Item Statistics**

The variation of TOSI and TMSI answers are presented in a Likert scale across a series of maps (Figure 3). The Likert scale ranged from 1 to 5, where 1 represents strongly disagree and 5 represented strongly agree. The TOSI and TMSI were the three questions' [Appendix A, Questions 1–6] average values combined on the respective indexes. of maps (Figure 3). The Likert scale ranged from 1 to 5, where 1 represents strongly disagree and 5 represented strongly agree. The TOSI and TMSI were the three questions' [Appendix A, Questions 1–6] average values combined on the respective indexes.

The variation of TOSI and TMSI answers are presented in a Likert scale across a series

**Cronbach's Alpha if Item Deleted**

**Figure 3.** Range of answers to individual Likert scale questions that are used to generate the multimeric indices of ownership [TOSI] and maintenance [TMSI] for the study area. **Figure 3.** Range of answers to individual Likert scale questions that are used to generate the multimeric indices of ownership [TOSI] and maintenance [TMSI] for the study area.

In the questions associated with TOSI and TMSI, most of the answers per zip code were higher than 3 on the Likert scale, except for satisfaction with neighborhood trees. The eastern zip codes had lower satisfaction with the number of trees than the western zip codes. In the question about tree health, the western zip codes had a higher rate on the Likert scale. A zip code in NW, a high-income and high canopy part of the study area, scored the lowest value for trees' importance.

#### 3.3.2. Public Perceptions of Urban Ecosystem Services

The results indicated that most of the participants had trees on their private property. The average percentage of participants that informed having trees on their yard was 94.2%. The lowest rate of private property trees was 75.8%, in the zip code 97209, an urban renewal area (redevelopment of industrial and low-income areas in inner-city) in Northwest Portland [31].

The last question about urban forestry perceptions was open-ended and we coded the answers using UES typology (Table 7). According to the coded answers, the strategies recommended a focus on urban forestry management (56.1%), cultural ecosystem services (31.5%) and regulating and provision services (12.4%).

**Table 7.** Public perceptions of relevant strategies to increase urban tree canopy.


Within the management challenges, 33.6% of the answers suggested financial solutions. The answers recommended the municipality to seek partnerships with volunteer associations, donation of seedlings and financial support for homeowners and renters, such as tax and water/sewage bill discounts. The second most mentioned typology was the maintenance of trees, with 18% of answers showing that respondents were aware of tree health and upkeep's essential requirements. The participants informed that proper tree pruning, tree species selection, tree debris removal and regulation for trees in developed areas were their top priorities.

Among the UES, knowledge systems and cultural heritage were the most significant concerns, holding 11% and 9.6% of the answers, respectively. Knowledge systems associated with urban forestry solutions that educate the population on how to take care of trees. Connection with teaching opportunities through schools and training programs can

prepare present and future generations to maintain trees and understand urban ecology interactions. Awareness of cultural heritage indicated the respondents' related urban forestry to community development, community engagement and neighborhood pride. The open-ended answers recommended tree planting events to promote activities that bring interaction among neighbors to praise trees' values for multiple cultures and ethnicities.

As most of the answers indicated strategies using financial solutions and tree maintenance, we conducted a separate analysis only with the UES typology. Excluding the management challenges (Table 7), knowledge systems and cultural heritages lead the answers with 25.1% and 21.8% of the responses, respectively. Natural heritage was the third most important, with 15.5% of answers. Natural heritage responses concerned the loss of mature trees, biodiversity and wildlife habitat. The respondents commented that small trees could take longer to provide the ecosystem services promoted by centenary trees susceptible to removal for new developments or infrastructure challenges.

The final analysis described the Spearman correlation between survey answers and the percentage of tree canopy per zip code (Table 8). The variables that had the strongest positive correlation with tree canopy were satisfaction with neighborhood trees (R = 0.767), satisfaction with tree health (R = 0.704), TOSI (R = 0.758) in a 0.01 significance level and aesthetics and inspiration (R = 0.453) in a 0.05 significance level. Though these are general findings, we note that these levels of significance and strength of the relationship varied by zip code.


**Table 8.** Correlation between tree canopy and survey answers about public perceptions of urban forestry.

\* Level of significance = 0.05; \*\* Level of significance = 0.01.

#### *3.4. How Do Neighborhood Trees and Socioeconomic Indicators Mediate the Public Perceptions of Ecosystem Services Availability?*

Seven out of eight zip codes in Portland's western sectors had a canopy rate higher than the eastern sectors. The justification for the uneven distribution is associated with the early conservation practices of urban forestry in the western zip code sectors [23], the hilly geological formation [26,27] and the higher income [8]. Tree canopy had a significant positive relationship to TOSI indicators and cultural UES of aesthetics and inspiration (Table 8). However, the excessive canopy does not please everyone, as expressed in the following statements from participants living in high canopy areas:

Too many trees already. While they have benefits, the trees need to be healthy and co-exist safely with residents. This requires regular, vigilant maintenance, which a lot of people (...) fail to do. We've repeatedly witnessed the tragedy of human deaths and property destructions, especially this last winter. Even one death is too many! We need to take better care of the existing trees before we consider adding more. (97221—Southwest)

I don't necessarily think the city should plant more trees. While the trees here certainly help relieve heat we need to be mindful of how little sun we get here (in Portland rainy weather). I think the city needs to maintain a balance between densely wooded areas (e.g., Forest Park) and highly exposed areas (e.g., central eastside). I think students and volunteers could plant lots of trees. (97221— Southwest)

(...) determine the most aesthetic and functional places to plant trees and then only plant trees that make logical sense for the conditions present in the chosen locations. (97210—Northwest)

I think the city should plant fruit and nut trees when they plant trees. They grow just as easy as any other tree. Most have beautiful flowers and foliage. And better yet they make healthy snacks especially in low income neighborhoods and food deserts. (97236—East)

(...) I can't see cars coming at intersections because there are too many trees already in my neighborhood. There is a near miss almost every day at my house because people can't see the cars coming. (97212—Northeast)

East of the Willamette River, five zip codes stood out with more than 10% of canopy cover. The zip code 97236 had 23.5% canopy cover in the Pleasant Valley area, an early incorporated neighborhood near an affluent suburb, Happy Valley. This zip code area also bears Powell Butte Natural Area, a remaining forest fragment. 97212 had 17% of tree coverage and the fourth largest average income citywide. 97202 had 13.8% of canopy cover and a protected riparian zone in the eastbound of Willamette River. 97215 had 13% of canopy cover and a preserved forest fragment on Mount Tabor Park. 97266 had 12.4% of tree coverage and was the third-lowest income zip code. However, it bears a forest fragment on Kelly Butte Natural Area. These findings showed that tree canopy follows income and geological formation features, such as riverbanks, forest fragments and hilly areas.

In low-income communities, trees' maintenance is observed as a financial burden, which can be classified as an ecosystem disservice [43]. Two zip codes from the East sector answered that 8.3% and 7.7% of the increasing tree canopy strategies have financial burden as a management challenge. The average answer mentions for financial burden was 4.5% per zip code. Seven out of eleven neighborhoods with answers above average are in the East, the sector with the lowest income and low canopy (Table 4). The following statements extracted from the open-ended question about strategies for increase tree canopy reflect the concerns for financial burden within residents of low-income neighborhoods:

"Offer to plant them (trees), offer low income solutions to families" (97233—East)

(...) lots of trees (are) in bad places and they die so better planning would do just fine and offering classes for ppl (people) who want to learn how to maintain the trees better and if they have it why does low income not have access to the classes and knowledge of them? (97233—East)

Don't charge for leaf cleanup. Offer a small tax credit for trees planted and maintained to property owner(s). Education regarding the importance of trees for everyone. Offer education to grow trees in a pot. Then everyone can grow a tree. (97220—East)

(...) more financial and volunteer support to groups like that (street tree planting nonprofit). Also when Portland had the ice storm this past winter, many residential trees came down. (...) people could bring downed trees and branches, maybe

even for a donation. Free mulch for the city and donations! Tree culture need(s) to be supported in more ways than just plantings (...) to make owning trees easy. (97220—East)

I'm sure a lot of people are scared away from that program (street tree planting program) due to the need to care for the tree and the possible damage to sidewalks that they will eventually be forced to repair at their expense later on down the line. (97220—East)

The answers for increasing canopy strategies also indicated concerns for other UES, such as climate change, knowledge systems, natural heritage and cultural heritage. Excluding the answers about management challenges, responses about regulating and provisioning UES represented 28% and cultural UES accounted for 72% of answers. We believed that people highly value cultural benefits from trees in urban areas due to the "extinction of experience" [3]. Within cultural ecosystem services, we distinguished patterns in responses that seek environmental education, multiple ethnic values for forest biodiversity and conservation of heritage trees. The answers associated with knowledge systems indicated that besides incentives for tree planting, people also need to know how to care for trees and their importance regarding ecosystem services. Public surveys assessing urban forestry and management of UES have suggested the enforcement of knowledge systems [44]. As observed in the previous statements, the survey participants repetitively suggested partnerships with education institutions, urban forestry jobs, internships and free workshops. The responses indicated that the residents expect more personal accountability for ownership if they have access to knowledge, tools and technical support from municipality and nonprofits.

In answers that mentioned cultural heritage, people requested more planting events to bond with neighbors and create a sense of community. The participants asked for multilingual tree support, public participation in urban forestry planning and access to trees with ethnic values regarding inclusion and diversity measures. Natural heritage answers indicate the population's willingness to perpetuate biodiversity, urban ecology and centenary trees. Together, cultural and natural heritage are UES that reflect landscape interpretations, which are individual perspectives of the environment based on personal background, memories, experiences and expectations. In general, environmental planning bears management tools that can perpetuate systemic racism by restricting access to ecosystem services based on socioeconomic values, reducing maintenance costs in areas with low-income and people of color and not acknowledging the diversity of behaviors in public space [45,46]. Surveys, interviews and focus groups can collect ideas, perspectives and expectations from historically unheard voices and open a path for public participation in urban forestry planning.

Portland had a complex history of gentrification that burdened the black community with displacement, loss of sense of spatial identity and identity representation [21]. The increase in population promoted real estate development for housing, business and other civic infrastructures. In Portland, there is an inverse relationship between canopy cover and urban development indicators, as water pipers [10]. The survey answers indicated that people are aware that new developments threaten trees, impacting their maintenance and natural heritage. The following statements are from the zip codes with lower housing ownership [Appendix B, Table A1] and most gentrified areas [32]:

"Yes, we need many more trees but (...) focus on protecting the most mature trees as they have been shown to provide the greatest benefits." (97227—North)

Demolition review to ensure maintenance of entire tree canopy as development can remove existing trees. The accelerated development in Portland has not been counterbalanced with a comprehensive plan to prevent tree removal and plant new trees. It has greatly reduced potential green spaces which could offset somewhat the unbridled concrete development. (97232—Northeast)

Trees are natural green infrastructures that support stormwater catchment, avoid erosion and improve air quality. Other forms of green infrastructure such as rain gardens, green roofs, artificial wetlands and parks can bring green gentrification—a gentrification process caused by the implementation of green infrastructures. The following Discussion section will explore how the results are associated with environmental justice and landscape management.

#### **4. Discussion and Conclusions**

This study aimed to address questions about the relationship between the existing amounts of neighborhood tree canopy with sociodemographic data and community perspectives. One of the explicit goals of the present study was to understand the relationship between tree ownership, maintenance and the amount of tree canopy. We found that zip codes with higher tree canopy were consistent with greater sense of ownership and quality of trees, as measured by the TOSI. Specifically, the two TOSI questions about the number of trees and the good condition of trees had a strong correlation and high significance values with tree canopy. This finding is consistent with a low Cronbach's alpha, suggesting that this metric can be explored further, perhaps in a different setting.

Our findings also indicate that a sense of ownership comprises the importance and satisfaction with the quantity and the quality of trees in the neighborhood, including trees in private property, public spaces and the right-of-way. Affluent zip codes had higher canopy cover had a higher correlation with public maintenance of street trees, as measured by the TMSI. While earlier research suggests that tree canopy and income are correlated in the U.S. [8–10], the perception of tree ownership is a new concept that brings accountability of ownership and maintenance in relation to urban ecosystem services. We observed a lower correlation between the tree canopy and TMSI than with TOSI (Table 8). TMSI also presented a lower range of mean values on the Likert scale response (Table 6), suggesting a common concern about tree care citywide (Figure 3). In the question about increasing tree canopy strategies, the responses about tree maintenance represented about 18% of the answers (Table 7).

Perhaps one of the most germane findings in our study is the fact that while a canon of literature describes the importance of trees in providing UES (e.g., pollination, air quality, climate regulation, etc.), our survey findings indicate that issues about management and cultural ecosystems services feature prominently among the respondents. This finding, while perhaps mundane, is significant for several reasons, including the fact that respondents seem to recognize the financial burden and maintenance when considering trees. If this finding is consistent across the city, then municipal goals for expanding tree canopy will face formidable obstacles if they present trees an important for traditional regulating ecosystem services. Rather, recognizing that communities are considering, perhaps less these regulatory services, than those surrounding maintenance and financing, may provide more effective.

Suitable messaging may not be the only implication of this finding. If aesthetics, inspiration and level of ownership are correlated with the amount of neighborhood tree canopy (Table 8), then attempts to create distributional equity will require considerable recognition of the maintenance costs involved. Maintenance often includes the planting appropriate species, pruning of trees, watering and a host of other monitoring to ensure healthy growth. Responses indicated the importance of maintenance and also suggested that municipalities provide support to those communities how may not have the financial resources to address maintenance concerns. Currently the City of Portland requires adjacent property owners to maintain all public trees, which increases the level of inequity already experienced by lower income communities. Perhaps the positive and significant correlation between income and presence of tree canopy is because lower income community may not prefer trees due to the cost of maintenance, which the open-ended responses indicated. The development of trees in the right-of-way interacts with other infrastructure, such as sidewalks, residences and transit features. Studies that observe the growth and health of

street trees [47], suggest regular monitoring and maintenance such as root pruning and interaction with underground infrastructures [48–50] which can help to ensure a healthy and robust tree canopy.

While these findings offer a first step towards integrating community perspectives into urban forest management, the findings suggest the importance of engaging communities in the management of tree canopy. The open-ended results suggested that respondents genuinely understand the challenges facing urban forest management and the importance of finding systematic ways to maintain canopy and provide equitable access to all residents. Our findings indicate, for example, that promoting financial solutions that optimize public and private budgets toward urban forestry and cultural heritage practices that engage the community in participatory planning and empowerment are the priority strategies for increasing tree canopy. With the multiple goals for achieving environmental equity through urban forestry, these strategies must also include raising awareness about the inequitable distribution of existing tree canopy, planting more trees in vulnerable communities, exploring diverse perspectives about climate resilience and exploring the role of trees among historically marginalized communities [46].

This study offers a means for understanding the importance of ownership and maintenance in addressing urban ecosystem services. While our survey can help to underscore some of these priorities, we recognize that engaging communities about urban forestry may pose several challenges. If employed effectively, other data collection methods, including listening sessions, focus groups and interviews, can help to contextualize urban forestry within the broader set of community needs that may be priorities. The COVID-19 pandemic has made clear that priorities such has housing, food and medical care are often front-andcenter among POC and lower income communities, which may pose several challenges for discussions about urban forestry. Since POC and low-income neighborhoods have been excluded from planning for a healthy and abundant urban forest [8], a pattern that may be associated to redlining practices in the U.S. [51] perhaps the built and natural environment in neighborhoods can be a direct means for understanding other pressing priorities. By engaging historically disinvested communities and address distributional injustices that have created current inequities in the distribution of tree canopy cover, municipal agencies may find creative solutions that 'multi-solve' the myriad pressing challenges.

Our study found that survey respondents seeks more measures and strategies to address cultural UES, such as cultural heritage, natural heritage, aesthetics and inspiration. The gap of systematic descriptions for these cultural UES within municipal plans may require greater levels of public involvement, which would build on diverse perspectives [46]. While government agencies are often responsible for the management of public spaces, the same agencies may not be trusted allies with communities that have been historically disinvested. As such, management options that engage community-based organization (CBOs) may be a more trusted and effective approach for soliciting plausible solutions. Such CBOs can work with community members to explore their expectations for land use, tree canopy, species selection, planting events, tree giveaways and volunteer workforce.

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. Both authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544-014) and the Robert Wood Johnson Climate and Health project. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. have read and agreed to the published version of the manuscript. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544 have read and agreed to the published version of the manuscript. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544 have read and agreed to the published version of the manuscript. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544 collected the survey data, coordinated the researched, and reviewed the manuscript. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the collected the survey data, coordinated the researched, and reviewed the manuscript. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number: 221077/2014-6—LASPAU—Brasil/CNPq—GDE—EUA; and by the

have read and agreed to the published version of the manuscript.

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

gested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have

and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and

costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies sug-

have read and agreed to the published version of the manuscript.

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

have read and agreed to the published version of the manuscript.

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

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have read and agreed to the published version of the manuscript.

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

Tree Ownership Satisfaction Index (TOSI):

**Appendix A Survey:**

manuscript, and in the decision to publish the results.

**Appendix A Survey:**

Strategies for increase tree canopy:

Strategies for increase tree canopy:

Q11 What is your home zip code?

Q11 What is your home zip code?

European ❑ White ❑ Other (please specify).

Demographic Questions:

Q8 Do you have trees at the property where you live? Yes/No.

gree/Strongly Disagree.

Presence of trees in private properties:

Q7 How do you think the city should get more trees planted?

Q8 Do you have trees at the property where you live? Yes/No.

Strategies for increase tree canopy:

Q11 What is your home zip code?

European ❑ White ❑ Other (please specify). Q11 What is your home zip code?

rican ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern

Demographic Questions:

gree/Strongly Disagree.

Presence of trees in private properties:

Strategies for increase tree canopy:

Presence of in private properties:

right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disa-

Q7 How do you think the city should get more trees planted?

Q8 Do you have trees at the property where you live? Yes/No.

Q7 How do you think the city should get more trees planted?

Q8 Do you have trees at the property where you live? Yes/No.

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

Examples of such cross-sectoral urban forestry management are emerging. In Toronto, CBOs had a more diverse species list than municipal agencies, landscape architects and nurseries [52]. In Detroit, interviews with CBO staff and recipients of giveaway trees informed that the ability to choose the tree species is a fact that impacts the willingness of residents to care for private trees, as well as live in areas with lower canopy. In both cases, studies have found that the major challenges are concerns with maintenance practices and costs, such as pruning, sidewalk damages and tree debris removal [53]. Both studies suggested stewardships for a functioning and healthy urban forestry, where CBOs would have the goal to promote understanding, while supporting cultural ecosystem services.

> **Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

> > have read and agreed to the published version of the manuscript.

have read and agreed to the published version of the manuscript.

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

Tree Ownership Satisfaction Index (TOSI):

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

**Author Contributions:** L.A.C.N. have performed the analysis and wrote the manuscript. V.S. have collected the survey data, coordinated the researched, and reviewed the manuscript. All authors

have read and agreed to the published version of the manuscript.

**Appendix A Survey:**

**Appendix A**

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

**Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. 014) and the Robert Wood Johnson Climate and Health project. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the 014) and the Robert Wood Johnson Climate and Health project. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the 014) and the Robert Wood Johnson Climate and Health project. **Conflicts of Interest:**The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in collection, analyses, or interpretation of data; in the writing of the US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role US Forest Service's National Urban and Community Forestry Challenge Grant (17-DG-11132544- 014) and the Robert Wood Johnson Climate and Health project. **Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role

manuscript, and in the decision to publish the results.

**Appendix A Survey:**

#### **Appendix A Appendix A Appendix A** manuscript, and in the decision to publish the results. in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

**Survey: Survey: Survey: Appendix A**

Tree Ownership Satisfaction Index (TOSI): Tree Ownership Satisfaction Index (TOSI): **Survey:** Tree Ownership Satisfaction Index (TOSI): Tree Ownership Satisfaction Index (TOSI): **Survey:** Tree Ownership Satisfaction Index (TOSI): **Survey: Survey: Appendix A Appendix A**

**Appendix A**

**Appendix A**

**Appendix A**

**Appendix A**

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

*Land* **2021**, *10*, x FOR PEER REVIEW 18 of 24

have read and agreed to the published version of the manuscript.

have read and agreed to the published version of the manuscript.

Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. Tree Ownership Satisfaction Index (TOSI): Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. Tree Ownership Satisfaction Index (TOSI): Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. Tree Ownership Satisfaction Index (TOSI): Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree /Strongly Disagree. **Survey:** Tree Ownership Satisfaction Index (TOSI): Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree Tree Ownership Satisfaction Index (TOSI): Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree **Survey:** Tree Ownership Satisfaction Index (TOSI): Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree **Survey:** Tree Ownership Satisfaction Index (TOSI): **Survey:** Tree Ownership Satisfaction Index (TOSI):

Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disagree/ Strongly Disagree. Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disa-Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disa-Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disa-Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disa-Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disa-/Strongly Disagree. /Strongly Disagree. /Strongly Disagree. Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree Q1 Portland's trees are important to me. Strongly Agree/Agree/Don't Know/Disagree

Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Tree maintenance Satisfaction Index (TMSI). Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Tree maintenance Satisfaction Index (TMSI). gree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly gree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly gree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. gree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. gree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly /Strongly Disagree. Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disa-/Strongly Disagree. Q2 My neighborhood has enough trees: Strongly Agree/Agree/Don't Know/Disa-

Tree maintenance Satisfaction Index (TMSI). Tree maintenance Satisfaction Index (TMSI). Tree maintenance Satisfaction Index (TMSI). Agree/Agree/Don't Know/Disagree/Strongly Disagree. Agree/Agree/Don't Know/Disagree/Strongly Disagree. gree/Strongly Disagree. gree/Strongly Disagree.

Q4 The city should maintain all trees along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q4 The city should maintain all trees along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q4 The city should maintain all trees along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q4 The city should maintain all trees along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q4 The city should maintain all trees along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Tree maintenance Satisfaction Index (TMSI). Q4 The city should maintain all trees along the street (in the public right-of-way, next Tree maintenance Satisfaction Index (TMSI). Q4 The city should maintain all trees along the street (in the public right-of-way, next Tree maintenance Satisfaction Index (TMSI). Q4 The city should maintain all trees along the street (in the public right-of-way, next Tree maintenance Satisfaction Index (TMSI). Q4 The city should maintain all trees along the street (in the public right-of-way, next Tree maintenance Satisfaction Index (TMSI). Q4 The city should maintain all trees along the street (in the public right-of-way, next Agree/Agree/Don't Know/Disagree/Strongly Disagree. Tree maintenance Satisfaction Index (TMSI). Agree/Agree/Don't Know/Disagree/Strongly Disagree. Tree maintenance Satisfaction Index (TMSI). Agree/Agree/Don't Know/Disagree/Strongly Disagree. Tree maintenance Satisfaction Index (TMSI). Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q3 The trees in my neighborhood are in good condition and healthy. Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree.

Q5 The city should prioritize maintenance of trees along the street (in the public right-ofway, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly Q4 The city should maintain all trees along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public right-Q4 The city should maintain all trees along the street (in the public right-of-way, next the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public right-Q4 The city should maintain all trees along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public right-Tree maintenance Satisfaction Index (TMSI). Q4 city maintain all trees along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Tree maintenance Satisfaction Index (TMSI). Q4 The city should maintain all trees along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree.

Q6 The city should plant trees in all available spaces along the street (in the public rightof-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disa-Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disa-Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disa-Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disa-Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disaof-way, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public of-way, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public of-way, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q6 The city should plant trees in all available spaces along the street (in the public Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree. Q5 The city should prioritize maintenance of trees along the street (in the public rightof-way, next to the sidewalk area) in low-income communities: Strongly Agree/Agree/Don't Know/Disagree/Strongly Disagree.

Strategies for increase tree canopy: Strategies for increase tree canopy: Strategies for increase tree canopy: gree/Strongly Disagree. gree/Strongly Disagree. gree/Strongly Disagree. right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disaright-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disa-Q6 The city should plant trees in all available spaces along the street (in the public Q6 The city should plant trees in all available spaces along the street (in the public

Q7 How do you think the city should get more trees planted? Q7 How do you think the city should get more trees planted? Q7 How do you think the city should get more trees planted? Q7 How do you think the city should get more trees planted? Strategies for increase tree canopy: Strategies for increase tree canopy: Strategies for increase tree canopy: Strategies for increase tree canopy: gree/Strongly Disagree. gree/Strongly Disagree. gree/Strongly Disagree. right-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disaright-of-way, next to the sidewalk area): Strongly Agree/Agree/Don't Know/Disa-

Presence of trees in private properties: Presence of trees in private properties: Presence of trees in private properties: Q7 How do you think the city should get more trees planted? Q7 How do you think the city should get more trees planted? Q7 How do you think the city should get more trees planted? Strategies for increase tree canopy: Strategies for increase tree canopy: gree/Strongly Disagree. gree/Strongly Disagree.

Q8 Do you have trees at the property where you live? Yes/No. Q8 Do you have trees at the property where you live? Yes/No. Q8 Do you have trees at the property where you live? Yes/No. Q8 Do you have trees at the property where you live? Yes/No. Presence of trees in private properties: Presence of trees in private properties: Presence of trees in private properties: Presence of trees in private properties: Q7 How do you think the city should get more trees planted? Q7 How do you think the city should get more trees planted? Q7 How do you think the city should get more trees planted? Presence of trees in private properties: Strategies for increase tree canopy: Strategies for increase tree canopy:

Demographic Questions: Demographic Questions: Demographic Questions: Q8 Do you have trees at the property where you live? Yes/No. Q8 Do you have trees at the property where you live? Yes/No. Presence of trees in private properties: Presence of trees in private properties: Q7 How do you think the city should get more trees planted? Q7 How do you think the city should get more trees planted?

Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000–\$79,999/ \$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 or more/I don't know. Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 or more/I don't know. Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 or more/I don't know. Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 or more/I don't know. Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 or more/I don't know. Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$79,999/\$80,000–\$89,999/\$90,000\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 Q8 Do you have trees at the property where you live? Yes/No. Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– Q8 Do you have trees at the property where you live? Yes/No. Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– Q8 Do you have trees at the property where you live? Yes/No. Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000–\$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– Presence of trees in private properties: Q8 Do you have trees at the property where you live? Yes/No. Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000– Presence of trees in private properties: Q8 Do you have trees at the property where you live? Yes/No. Demographic Questions: Q9 What is your household income? Less than \$10,000/\$10,000–\$19,999/\$20,000–

Q10 Which best describes your race or ethnicity? Choose as many as apply: Q10 Which best describes your race or ethnicity? Choose as many as apply: Q10 Which best describes your race or ethnicity? Choose as many as apply: Q10 Which best describes your race or ethnicity? Choose as many as apply: Q10 Which best describes your race or ethnicity? Choose as many as apply: or more/I don't know. or more/I don't know. or more/I don't know. or more/I don't know. or more/I don't know. \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 \$29,999/\$30,000\$39,999/\$40,000\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000– \$29,999/\$30,000–\$39,999/\$40,000–\$49,999/\$50,000–\$59,999/\$60,000–\$69,999/\$70,000–

❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ African ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern European ❑ White ❑ Other (please specify). Alaska Native ❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ African ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern European ❑ White ❑ Other (please specify). American Indian/Native American ❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ African ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern European ❑ White ❑ Other (please specify). East Asian Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ African ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern European ❑ White ❑ Other (please specify). South Asian Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑Alaska Native ❑ American Indian/Native American ❑ East Asian ❑South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ African ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern Southeast Asian Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ African ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern West Asian Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑ Alaska Native ❑ American Indian/Native American East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ African ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern Middle Eastern Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ African ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern Black or African American Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ African ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern African or more/I don't know. Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ Af-Hispanic or Latino or more/I don't know. Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ Af-Native Hawaiian or Pacific Islander more/I don't know. Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ Af-Slavic or Eastern European \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 or more/I don't know. Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑ Alaska Native ❑ American Indian/Native American ❑ East Asian ❑ South Asian White \$79,999/\$80,000–\$89,999/\$90,000–\$99,999/\$100,000–\$149,999/\$150,000–\$199,999/\$200,000 or more/I don't know. Q10 Which best describes your race or ethnicity? Choose as many as apply: ❑ AlaskaNative ❑ American Indian/Native American ❑ East Asian ❑ South Asian Other (please specify).

Q11 What is your home zip code? Q11 What is your home zip code? European ❑ White ❑ Other (please specify). European ❑ White ❑ Other (please specify). European ❑ White ❑ Other (please specify). rican ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern rican ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern ❑ Southeast Asian ❑ West Asian ❑ Middle Eastern ❑ Black or African American ❑ Af-❑ Southeast Asian West Asian ❑ Middle Eastern ❑ Black or African American ❑ Af-Q11 What is your home zip code?

European ❑ White ❑ Other (please specify). Q11 What is your home zip code?

Q11 What is your home zip code?

European ❑ White ❑ Other (please specify). Q11 What is your home zip code?

Q11 What is your home zip code? Q11 What is your home zip code? Q11 What is your home zip code? Q11 What is your home zip code? European ❑ White ❑ Other (please specify). European ❑ White ❑ Other (please specify). European ❑ White ❑ Other (please specify). rican ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern rican ❑ Hispanic or Latino ❑ Native Hawaiian or Pacific Islander ❑ Slavic or Eastern Q12 Do you rent or own the place where you live? Rent/Own.

Q11 What is your home zip code?

*Land* **2021**, *10*, 48
