Microclimatic and Environmental Improvement in a Mediterranean City through the Regeneration of an Area with Nature-Based Solutions: A Case Study

Round 1

Reviewer 1 Report

Manuscript ID: Sustainability-1670345-peer-review-v1

Title: Microclimatic and environmental improvement in a Mediterra- nean city through the regeneration of an area with Nature- based Solutions: a case study

Journal: Sustainability

The article addresses a topic of interest and relevance, I have found the paper interesting,  but presents some methodological problems. My comments including major and minor concerns are given below:

• The abstract should consist of an easy to understand summary of the study, its methodology and obtained results. The abstract is too generic. Please give the numerical results in this section. Which scenario nature was successful. This should be specified.
• Introduction:The objectives of the study were defined. Given the number of studies in this research area;  what gap will this study fill in the literature?  For example, what is the contribution/novelty of this study? What kind of local and global knowledge the authors want to improve? The study has a couple of purposes, but it can have many goals.

Although the literature on the subject has been reviewed, expressions and structures should be increased. Please, look at this references: Regarding the discussion, the authors should further compare their findings with references. Link your findings with those from previous studies and this will also help make more broader conclusions. Please use the following references on tree species, landscape design, related to planning management.

• Qaid A, Ossen DR (2015) Effect of asymmetrical street aspect ratios on microclimates in hot, humid regions. Int J Biometeorol 59(6):657–
• *Yilmaz S., Mutlu B. E., Aksu A., Mutlu E., Qaid A.,2021 "Street design scenarios using vegetation for sustainable thermal comfort in Erzurum, Turkey", Environmental Science and Pollution Research, 28 (3): 3672-3693. DOI10.1007/s11356-020-10555-z

* *Yilmaz S., Mutlu E., Yılmaz H., 2018. Alternative Scenarios For Ecological Urbanizations Using Envi-Met Model.  Environmental Science and Pollution Research, 25 (26): 26307–26321 ;  doi: 10.1007/s11356-018-2590-1

• Materials and Methods are descriptive and provide information related to the input data and the methodology used in the study. As for the methods, I suggest inserting few lines synthesizing the structure of the section, which has many subsections. There is a main point that need to be discussed about ENVImet, which is particularly important for your work: how does ENVImet consider the effect of vegetation on microclimate parameters? On which equation its calculation are based? Is it considering only shading or also evapotranspiration? As the focus of the manuscript is on vegetation, these are all considerations that need to be in depth described and considered in the methodology section.

*The measuring station or meteorological data point should be shown in figure 1.

*Figure 1 should be cited first in the text. After fig. 2 ( pace (3) line (116-122).

*Latin of the plants and name preferred in the analysis should be given here (2.2.Criteria for plant selection). Images of preferred plants in that region can also be given.

*In table 4, the tree "Cercis siliquastrum" is indicated as both coniferous and leafy.

*Why were the plant names listed in Table 5 given? should be explained. Because not all of them were used in the analysis.

*In Table 6, min and max mean values should be given separately for each scenario. In this state, the values of the scenarios are not detected.

• Results: As for conclusion and discussion, I suggest adding a few lines synthesizing the structure of the section with many subsections. Accuracy analysis must be added to this study. Please see references above---"ENVI-met model validation" (Qaid and Ossen, 2015; Yilmaz et al., 2021). Statistical analysis seems appropriate. However, the results should be reflected in the findings.
• The discussion part should be a little stronger. Generally, only the findings are given. Research findings should be discussed with other studies. This part is very important. Reference should be increased in discussion.
• The conclusion section contains study result expressions. Generally, this paper is a very good submission especially Tables. But, Tables, min and max mean values should be given separately for each scenario. Features can be given instead of scenario number. It will be more perceptible to the reader.

The present work could be interesting for the future urban planning for suistanable cities. But this research has major methodological flaws. Discussion should be stronger more than now. Please, relevant literatures should be consulted and discussed.

Comments for author File: Comments.pdf

Author Response

The article addresses a topic of interest and relevance, I have found the paper interesting, but presents some methodological problems.

Thank you very much for your valuable comments and suggestions. Find our point-by-point response below.

My comments including major and minor concerns are given below:

➢ The abstract should consist of an easy to understand summary of the study, its methodology and obtained results. The abstract is too generic. Please give the numerical results in this section. Which scenario nature was successful? This should be specified.

Suggestion taken. Abstract was reorganized adding microclimatic values related with plant biomass increase and deleting some sentences to fit the 200 words limit given by the Sustainability.
Based on our results, each scenario showed some performing values in terms of air temperature, wind speed, etc. As a consequence, stating that we obtained a successful scenario for all the microclimatic parameters taken into account could be misleading,since it is the combination of different layer, coverage and type of vegetation that resulted in different mitigation of the microclimatic extreme. Data in the abstract and in the discussion section were added to clarify this point.

➢ Introduction: The objectives of the study were defined. Given the number of studies in this research area; what gap will this study fill in the literature? For example, what is the contribution/novelty of this study? What kind of local and global knowledge the authors want to improve? The study has a couple of purposes, but it can have many goals.

Although the literature on the subject has been reviewed, expressions and structures should be increased. Please, look at these references:

Regarding the discussion, the authors should further compare their findings with references. Link your findings with those from previous studies and this will also help make more broader conclusions. Please use the following references on tree species, landscape design, related to planning management.

• Qaid A, Ossen DR (2015) Effect of asymmetrical street aspect ratios on microclimates in hot, humid regions. Int J Biometeorol 59(6):657–677.
• Yilmaz S., Mutlu B. E., Aksu A., Mutlu E., Qaid A.,2021 "Street design scenarios using vegetation for sustainable thermal comfort in Erzurum, Turkey", Environmental Science and Pollution Research, 28 (3): 3672-3693. DOI10.1007/s11356-020-10555-z
• Yilmaz S., Mutlu E., Yılmaz H., 2018. Alternative Scenarios For Ecological Urbanizations Using Envi-Met Model. Environmental Science and Pollution Research, 25 (26): 26307–26321; doi: 10.1007/s11356-018-2590-1

Thanks for comments and suggestions.

We have rephrased some of the study aims to better clarify the novelty of the paper compared with current literature.

We added this sentence (line 80-81): ”Validations of the accuracy of the model results have been widely shown by several previous studies [41–44]” where we took into account additional literature including some of the papers suggested by the reviewer.

In the Introduction section we also added these sentences (line 84-93) to clarify software used (including version) and missing points.

“The ENVI-met V4.4.5 software allows to build models with simple plants and 3D-plants. Simple plants essentially consist of simplified vegetation models, defined by plant height, ten-layers LAD, and ten-layers RAD [52]. 3D plants are digitized by the plant editing tool Albero, capable of digitizing complex plant models (e.g., trees) using groups of cells with a LAD and a RAD [53]. In ENVI-met V4 and later versions, the 3D modelling of a plant requires more detailed data on the physical features, compared to the previous version V3, which used simple vertical structures, similar to the simple plants [41]. However, the software plant database of V4.4.5 list only the most common plants – specifically trees - and the ‘plant properties’ partly matches real data (e.g., crown dimension, total height, kind of foliage, seasonality) [54,55];

In the study aims we added this sentence (line 100-103) to better clarify what are the gaps and the scale of this study: “The study focuses on a microscale case study, in order to fill the literature gap (i.e., few studies on such scale). A methodology to increase the accuracy of simulations, taking into account the right plant dimensions and related performances, is also developed and test, as means to evaluate the effects of NbS at small scale.”

➢ Materials and Methods are descriptive and provide information related to the input data and the methodology used in the study. As for the methods, I suggest inserting few lines synthesizing the structure of the section, which has many subsections.

Suggestion taken. In the M&M sections we added these sentences to provide a short resume of the structure as follows (line 120-125):

“The study evaluates the microclimatic effects of Nature based Solutions in a case study in the city of Genoa (site characteristics in section 2.1). Criteria for plant species selection are outlined in section 2.2 and three different design scenarios are presented in section 2.3. All scenarios were analysed by means of a microclimatic model (described in section 2.4), in terms of environmental parameters, plant species parametrization and data analysis.”

There is a main point that need to be discussed about ENVImet, which is particularly important for your work: how does ENVImet consider the effect of vegetation on microclimate parameters? On which equation its calculation are based? Is it considering only shading or also evapotranspiration?

The ENVImet software considers both shading and evapotranspiration to allow evaluating the vegetation effects on microclimatic parameters. We added this sentence to clarify this aspect (line 245-246): “The ENVI-met V4.4.5 takes into account shading and evapotranspiration to evaluate effect of vegetation on different microclimatic parameters.”

As the focus of the manuscript is on vegetation, these are all considerations that need to be in depth described and considered in the methodology section.

*The measuring station or meteorological data point should be shown in figure 1.

Suggestion taken. The position of meteo statio was added into figure 2 and related coordinates are given in sect. 2.4.2.

*Figure 1 should be cited first in the text. After fig. 2 (pace (3) line (116-122).

Thank you for the comment. Since figure from Mosca et al. need to be cited first, we changed the figure order accordingly.

*Latin of the plants and name preferred in the analysis should be given here (2.2.Criteria for plant selection). Images of preferred plants in that region can also be given.

All details related to plant species taken into account, especially the ones used in the different simulations, were already resumed in table 5.

Since the effect of different plant species and assemblages has the most impacting effect on local microclimate, we cannot state that there were preferred plant species.

*In table 4, the tree "Cercis siliquastrum" is indicated as both coniferous and leafy.

Thank you for the comment. Table 4 aimed to compare “default” values obtained from software database versus “modified” values. To make the table clearer we captured the two graphic interfaces of the software to highlight the differences in the dimensions and calendar. We modified the table as per reviewers’ suggestion.

*Why were the plant names listed in Table 5 given? should be explained. Because not all of them were used in the analysis.

Most suitable species were listed in table 5, only the ones with the highest number of characteristics matching with the required criteria stated in table 1 were used in simulations. We clarify this in the text (line 280-282) stating that: “Table 5 reports the first list of the plant species, following the criteria highlighted in table 1. Among them, only the ones that matches most of the criteria were used to be included in the scenarios”

*In Table 6, min and max mean values should be given separately for each scenario. In this state, the values of the scenarios are not detected.

Suggestion taken, thank you. Values were added. We also add a sentence in the table caption as follows (line 304-305): “Minimum and maximum values have been reported for each analysis, for the area corresponding to Piazza Metastasio, as highlighted in table (i.e., current state, air temperature).”

➢ Results: As for conclusion and discussion, I suggest adding a few lines synthesizing the structure of the section with many subsections.

Thank you for the comment. We added resume of the subsection in the M&M section, while Results and discussion had no subsection.

 

Accuracy analysis must be added to this study. Please see references above---"ENVI-met model validation" (Qaid and Ossen, 2015; Yilmaz et al., 2021).

Thank you for the suggestion. In this study we focused on different theoretical scenarios without comparison with the real condition, since the square was not completely vegetated yet and plants will require years to reach the dimension at maturity that will allow us to perform the correct comparison among parameters.

Statistical analysis seems appropriate. However, the results should be reflected in the findings.

Thank you for the comment. We added or reorganized some sentences adding data, level of significance, correlation coefficient, exact data reported, etc. (in comparison with data reported in table 6, 7, 8).

➢ The discussion part should be a little stronger. Generally, only the findings are given. Research findings should be discussed with other studies. This part is very important. Reference should be increased in discussion.

Thank you for the comment. We added more comparison with literatures. E.g. line 324-327 “The increase in air temperature in scenarios 2,3 (i.e., with greater greening) compared to scenario 1, may be due to the less ventilation of the area, caused by the presence of the gradual vegetation amounts in the scenarios, which could reduce the wind flow [70–72].

Line 363-364 “Several studies also show the wind role on the urban microclimate, although there may be many factors that can affect it [72,76–78].”

➢ The conclusion section contains study result expressions. Generally, this paper is a very good submission especially Tables. But, Tables, min and max mean values should be given separately for each scenario. Features can be given instead of scenario number. It will be more perceptible to the reader.

Thank you very much for your comment. We added minimum and maximum values and a short description of the different scenarios in the conclusion section.

Reviewer 2 Report

The paper deals with an interesting perception and problems of urban green areas design. The authors search for deeper causes and recognize various problems and perspectives, proposing long-term solutions that could be regulated through urban planning strategies, and possibly through different regulations. Paper is also a good example of raising awareness of the importance of green areas and NBS for better living conditions in the context of different pressures, urban climates and pollution.

Comments for author File: Comments.pdf

Author Response

Authors wish to thank we reviewer for the appreciation received and the evaluation.

We have improved the Results and Discussion and Conclusion section better supporting our key findings with literature (see answer to reviewer 1).

Reviewer 3 Report

Dear Authors,
The total area of cities in the world is set to expand dramatically over the next decades with negative consequences for people and the environment. Poor air quality, floods, droughts, heat waves, loss of biodiversity and the urban heat island phenomenon are just some of the serious effects of urban sprawl. A promising idea is to introduce nature-based solutions (NBS) - concepts inspired by nature and implemented to eliminate social and environmental problems.
The manuscript is well-written and fits well the general scope of Sustainability. The topic of the study presented is interesting and it includes a novelty.
The study shows the microclimatic effects of a small-scale regeneration project in the city of Genova, more specifically, in a dense urban area in Mediterranean areas characterised by relevant wellbeing and health issues (i.e., with high HERI and SMRs). Design scenarios with NbS, using a targeted selection of plant species, were designed and their microclimatic performances simulated by means of the software ENVI-met.
The study allowed selecting the most effective design strategy for the draft of a final design for a pilot redevelopment project. The most effective is the scenario with the highest coverage by herbaceous, shrub and tree layer.
Concluding, in my opinion: 1. The subject and research are innovative 2. The purpose of the research is well defined. 3. Analyzes carried out correctly. 4. The article is a perfect combination of theory and practice.

Comments for author File: Comments.pdf

Author Response

Authors wish to thank we reviewer for the appreciation received and the positive comment to the manuscript.

Round 2

Reviewer 1 Report

 At the present version of their manuscript I believe that I now are able express that their research is comprehensive for these type of areas and the results can easily be extended to regions of similar climate.