Tree and forest health is increasingly influenced by climate change as well as growing globalisation and trade. Climate change enables species to colonise new environments, and species that previously were constrained by native predators are now able to flourish in these new environments with little or no resistance. Additionally, the growing trade in live plants and wood products results in the inadvertent movement of species (such as pests or fungi in soil) from far away areas of the globe. As a result, new forest and tree risks may occur with the potential for significant impacts on forest and tree health. However, managing these impacts through legislation and policy is a challenge, particularly in terms of balancing a predominant free trade policy alongside substantial biosecurity concerns. This Special Issue highlights the social system considerations around forest health: the ways in which specific legislative and policy systems, at the national, regional or local level, aim at regulating or managing increasing invasive species risks and outbreak events; the ways in which policy instruments, technologies or management practices can be developed to manage tree pests and pathogens; and the socioeconomic and cultural implications of pest or disease outbreaks. It illustrates the possibilities and limitations in specific socioeconomic and political systems to manage and limit the impacts of increasing challenges to forest health under climate change and globalisation. Full article

Oak processionary moth (Thaumetopoea processionea) or OPM was accidentally introduced into London on imported oak trees and now poses a threat to the future of oak in the urban landscape. Early attempts at eradication of the moth failed and significant resources have since been spent by government on monitoring and controlling OPM (through the use of insecticides or bio-pesticides) as it spreads into new areas. OPM is regulated in the UK to minimize risk of new introductions and reduce spread. Surveying for OPM and issuing of statutory notices for control is based on a geographical system of core, control and protected zones. While OPM will defoliate the trees leaving them vulnerable to other pests and diseases and stress factors, the caterpillars can also harm people and animals via tiny urticating hairs with the potential for dermatological or respiratory impacts. However, the biggest threat to the iconic British oak may be that the perceived risks associated with OPM, and costs of management may lead land managers to fell their oak trees, and not plant oak in the future. There is a need to better understand awareness, risk perceptions and decision-making around OPM management. We use a conceptual framework to explore decision-making and the trade-offs between the social, economic and ecological values associated with oak trees, and assessment of risk related to both the moth and control options. Twenty nine interviews were conducted in two London boroughs and across Greater London and in some surrounding counties covering a range of land types (e.g., parks, school grounds, amenity areas and private gardens) with infested or non-infested oak. We found a lack of evidence of human health impacts from OPM although land managers were concerned about public duty of care and potential reputational damage if they do not manage OPM. To address the challenges of dealing with OPM, land managers were taking a risk-based approach and managing OPM where it posed the highest potential risk to people. Respondents expressed strong emotional attachments to oak but it also has high biodiversity value which can lead to difficult decisions about management options. A risk-based approach moves beyond a ‘one-size-fits-all’ control method and focuses available resources where they are most needed and socially acceptable. An approach that allows for multiple values and perspectives on risk may provide a more sustainable long-term option for OPM management to ensure the future of oak in the city. Full article

Ash dieback Hymenoscyphus fraxineus (T. Kowalski), is an alien fungal disease probably introduced to Europe from Asia that currently presents a significant threat to native ash (Fraxinus L. spp.). In the United Kingdom a large proportion of ash trees are found outside of woodlands. This means that a wide diversity of land owners and managers are stakeholders in the response to ash dieback. Local authorities (local government units) hold responsibility for managing ash trees along the highways and other public sites, with a focus on maintaining public health and safety. Developing local action plans (LAPs) for ash dieback is promoted by the government as way for local authorities to plan an effective strategic response at a landscape scale. However, risk assessment frameworks and the knowledge about ash dieback that is needed for quality decision-making at this level is still lacking. The scientific uncertainty around ash dieback progression, mortality rates, and the hazards presented by the trees at different stages of infection present knowledge problems. The research aims to (i) develop and evaluate an approach to addressing ash dieback suited to local authorities across the United Kingdom, and (ii) address the research gaps surrounding the local authority approaches to risk assessment and overcoming “knowledge problems.” Our hypothesis is that action research can be used to develop an effective risk assessment framework and knowledge tools that can improve decision-making. Our research questions in support of these objectives are: (i) How do local authorities perceive, assess, and plan for risks? (ii) What information and knowledge do local authorities need to assess and manage the specific risks of ash dieback? Lastly, (iii) what processes drive the local authorities toward preparing and implementing LAPs? Data collection occurred between 2015–2019 and included: deliberative co-production and validation workshops, two survey questionnaires, and evaluative semi-structured interviews (SSIs). Local authorities were shown to assess risk and proportionality of response to ash dieback through processes of deliberative social learning mixing opinion, scientific and practice-based knowledge to reach a consensus over the methods and knowledge that would be used in decision-making. Placing ash dieback on corporate risk registers that cut across the multiple departments dealing with the problem facilitated political approval, action planning, and budget allocation. Generating locally specific knowledge and finding the resources and personnel to drive forward strategic planning and implementation were key to landscape scale responses and ratifying LAPs. Collaborative action research working on ways of assessing, learning, and responding to tree pests and diseases offer an important approach to problem-solving and developing responses at the landscape scale. Full article

Research Highlights: This research advanced understanding of stakeholder relations within the context of innovation using citizen science in a biosecurity sociotechnical system (STS) in Aotearoa, New Zealand. Background and Objectives: It draws on recent experiences in the United Kingdom, where analysis of stakeholder engagement in the development of biosecurity surveillance technologies and citizen science initiatives have occurred to support understanding and development of forest and tree health biosecurity. Early detection technologies are essential as biosecurity risks to the primary sectors increase with the expansion of global trade and shifting pest dynamics that accompany a changing climate. Stakeholder engagement in technology development improves the chances of adoption but can also challenge the mental models of users in an existing STS. Materials and Methods: Two conceptual models that embed stakeholder relations in new information and communications technology (ICT) design and development were applied: (i) a future realist view of the general surveillance system incorporating citizen experts as species identifiers; (ii) a social construction of the ICT platform to surface mental models of the system in use creating the groundwork for evolution of stakeholder relations within STS innovation. A case study demonstrating how we addressed some of the practical limitations of a proposed systems change by applying sociotechnical innovation systems (STIS) theory to the development and adoption of new technologies for surveillance in the existing biosecurity system was presented. Results: Opportunities to enhance the capacity for early detection were considered, where the needs of diverse factors within a central government biosecurity authority and the wider citizenry are supported by the development of a general surveillance network (GSN). Full article

The emerald ash borer (EAB) was first detected in North America in 2002, and since its introduction, this invasive pest has killed millions of ash trees. While EAB kills native North American ash trees in all settings, its impacts have been especially large in urban areas where ash has been a dominant street tree, especially in residential areas. While some management costs, such as insecticide treatment, tree removal, or tree replacement, are relatively straightforward to compute, the impact that EAB has had on residential property values is less clear. To better understand the economic cost of EAB in urban settings, we conducted a hedonic property value analysis to evaluate the impact of ash tree damages due to EAB infestation on housing sales prices. This study was conducted in the city of Milwaukee, Wisconsin, which had high stocking levels of ash trees prior to EAB’s arrival. The objectives of the study are to investigate: (1) how EAB-infested ash trees affect property values; (2) whether the benefits from healthy ash trees to property value change after arrival of EAB; and (3) whether healthy ash trees located within infested neighborhoods provide the same benefits as the healthy ash trees located outside of infested neighborhoods. In general, our results show that the EAB outbreak has had a negative impact on home values for properties located in close proximity to the ash tree component of the urban forest. This result holds true for neighborhoods where EAB does not yet pose an imminent threat, and is amplified for neighborhoods where EAB has been detected. Our results highlight the early stages of a dynamic economic process that impacts urban residential property owners subject to the risk of EAB or other tree pests and diseases. In general, we find that forward-looking behavior of residential property owners is capitalized into property values during the process of forest pest infestation. Full article

This paper seeks to address the need for a more nuanced understanding of public perceptions of risk-related events by investigating the nature of and drivers for a ‘concerned public’ to an environmental issue, using the case study of the ash dieback outbreak in the UK. Q Methodology, an approach that combines both quantitative and qualitative data through factor analysis to identify different ways of thinking about a particular issue, was used to investigate the subjective response of local publics to ash dieback in East Kent, England, one of the early outbreak locations. Five narratives are identified, distinguishing perceptions of risk and management preferences: (1) call for better biosecurity; (2) resilient nature and techno-scientific solutions; (3) fatalistic; (4) disinterested; and (5) pro-active citizens. Four narratives demonstrated concern about the impacts of ash dieback on woodland ecosystems, but beliefs about whether the disease arrived in the UK on infected imported nursery stock or on windblown spores varied. The results of this study contribute to improving understanding of the drivers of differing public perceptions of tree health risks, an important consideration for designing socially acceptable strategies for managing tree pests and diseases, and other environmental risks, in the future. Full article

The challenges to forest health from climate change, globalization, contemporary trade practices and new recreational patterns require effective biosecurity. We asked: How is the biosecurity border for tree health understood and enacted by state and non-state actors? What are the consequences for tree health? Semi-structured interviews (N = 10) were conducted with scientists and other relevant actors (N = 21). The border was understood variously as: a biophysical boundary, often the coast; a geopolitical boundary, usually of the European Union; the points of main inspection focus; dispersed nodes of inspection; a ‘pre-border’ outside of UK; or by the location of detection activities. A wide range of state, non-state and hybrid groups are engaged in border practices. These practices have been altered due to trade and climate changes, are subject to cost and resource priorities and reflect particular knowledge flows and the biological nature of the agents. We suggest that there is an ‘everyone’ as well as ‘everywhere’ border that demands clarification of risks, roles and responsibilities, and we offer practical recommendations. We conclude that tree health border challenges are a manifestation of wider sustainability issues that enable us to explore human–nature relationships, democratic engagement and the pursuit of more sustainable futures. Full article

Evidence of increased biotic disturbances in forests due to climate change is accumulating, necessitating the development of new approaches for understanding the impacts of natural disturbances on human well-being. The recent Mountain Pine Beetle (MPB) outbreak in the western United States, which was historically unprecedented in scale, provides an opportunity for testing the adequacy of the life satisfaction approach (LSA) to estimate the impact of large-scale forest mortality on subjective well-being. Prior research in this region used the hedonic method (HM) to estimate the economic impacts of the MPB outbreak, and results are used here to evaluate the reasonableness of economic estimates based upon the LSA. While economic estimates based upon the LSA model do not appear to be unreasonable, several limitations in using the LSA for nonmarket valuations are discussed. New avenues for research that link the LSA with stated preference methods are discussed that appear likely to address major concerns with standard LSA models as used in nonmarket valuation. Full article

Forest health can be adversely affected by invasive organisms. Biosecurity measures to prevent the establishment of harmful invasive organisms at national points of entry (e.g., airports or shipping ports) are vital to protect forest health. Innovations in pest eradication technologies are being developed based on their efficiencies and effectiveness. However, the question of whether people find them acceptable is rarely considered. In New Zealand, research is underway into the use of highly targeted pesticide spraying using unmanned aerial vehicles (UAVs) as a novel technology to eradicate pest species that impact forest, food, and fibre sectors. Public approval for such technologies, however, can be a critical aspect for their success. A tool can be technically effective (achieve eradication), but uptake may be impossible if communities do not trust the technology. We developed a method for enabling discussions about the use of UAVs and their acceptability in general before being operationalized for biosecurity. This paper presents an investigation of how “participatory-design”, an often tactile, visual, and inclusive process of community engagement can improve the acceptance of technology use in the public sphere. We asked people, both scientists and citizens, to evaluate the acceptability of a range of UAV uses (including biosecurity) along a continuum and then explored the reasons for their placement. Key criteria for acceptable and unacceptable uses were subsequently developed to help technology designers and operators consider aspects of social acceptability during design processes. Our tool and approach facilitated discussions around technology acceptability that were subsequently adopted by our technical design team for the development and the use of acceptable UAVs for biosecurity. This research shows how systematic approaches to design can help uncover and mitigate social acceptability issues through inclusive design under increasing threats of biosecurity, whether related to challenges of trade or climate change. Full article

The European chestnut population is enduring multiple compounding exotic pest and disease outbreaks across Turkey. The deeply held value of the chestnut species for the Turkish public is reflected in substantial government conservation programming. Chestnut is predominantly found on state land managed by Turkey’s General Directorate of Forestry (GDF), which generally upholds restrictive policies for chestnut-related livelihood practices other than nut collection and beehive placement. Such policies are justified by a government position that human activities and presence is likely to worsen disease dynamics. Conversely, a growing body of research findings testify that small-scale livelihood practices maintain biological diversity and, furthermore, that this traditional maintenance of diversity has been correlated with decreased pathogen pressure within agroecosystems. However, few studies have investigated this phenomenon in the context of agroforestry systems. At a global ecological moment of increasingly pervasive and severe exotic forest pathogen impact, this paper investigates the influence of diverse small-scale livelihood practices and knowledge on chestnut tree health across the highly heterogenous geography of Turkey. We conducted ethnobotanical questionnaires with 96 chestnut-utilizing households, and chestnut tree health evaluations in georeferenced forest areas they identified, throughout Turkey’s Black Sea, Marmara, and Aegean regions. Using data from 1500 trees, we characterized the effects of subsequently recorded environmental, physiological, and anthropogenic factors on tree health using multiple correspondence analysis (MCA), multiple factor analysis (MFA), and mixed models. Our results show that the traditional human management of tree physiology and ecology has a significant positive effect on tree health, especially through the acts of grafting and culling as well as the maintenance of diversity. We argue that conceptualizing such livelihood systems as human niche construction and maintenance can help forest management agencies to better understand and conserve valuable landscapes, even in increasingly common periods of severe pathogenic pressure. Full article

The emerald ash borer (EAB) has caused extensive damage and high mortality to native ash trees (Fraxinus; sp.) in North America. As European countries battle with the deadly pathogen Hymenoscyphus fraxineus (ash dieback) affecting European ash (Fraxinus excelsior), there is concern that the arrival of EAB will signal the demise of this much-loved tree. While Europe prepares for EAB it is vital that we understand the social dimensions that will likely influence the social acceptability of potential management measures, and experiences from the USA can potentially guide this. We draw on differing sources including a literature review, documentary analysis, and consultation with key informants from Chicago and the Twin Cities of Minneapolis and St. Paul. In this paper, we focus on EAB management responses that involve chemical applications, tree felling and replanting, and biological control, and assess their likely social acceptability to stakeholders based on the perceived risks and benefits. Benefits involve protecting specific ash trees and slowing the spread of EAB across the landscape. Risks include collateral harm from insecticide use on human and environmental health, financial costs and liabilities, and the effectiveness of each approach. Biological control and replacing ash with other species are likely to be largely acceptable across contexts and stakeholder groups but pre-emptive felling and insecticide application could be more problematic if seeking widespread social acceptance. Based on our observations from the evidence collected we offer suggestions for approaching EAB management in Europe with a focus on improving prospects of social acceptability. Strong engagement will be necessary to establish the relevance and reason for using different management approaches and to build awareness and trust. Full article