The multidisciplinary ‘Phyto-threats’ project was initiated in 2016 to address the increasing risks to UK forest and woodland ecosystems from trade-disseminated Phytophthora. A major component of this project was to examine the risk of Phytophthora spread through nursery and trade practices. Close to 4000 water and root samples were collected from plant nurseries located across the UK over a three-year period. Approximately half of the samples tested positive for Phytophthora DNA using a metabarcoding approach with 63 Phytophthora species identified across nurseries, including quarantine-regulated pathogens and species not previously reported in the UK. Phytophthora diversity within nurseries was linked to high-risk management practices such as use of open rather than closed water sources. Analyses of global Phytophthora risks identified biological traits and trade pathways that explained global spread and host range, and which may be of value for horizon-scanning. Phytophthoras having a higher oospore wall index and faster growth rates had wider host ranges, whereas cold-tolerant species had broader geographic and latitudinal ranges. Annual workshops revealed how stakeholder and sector ‘appetite’ for nursery accreditation increased over three years, although an exploratory cost-benefit analysis indicated that the predicted benefits of introducing best practice expected by nurseries outweigh their costs only when a wider range of pests and diseases (for example, Xylella) is considered. However, scenario analyses demonstrated the significant potential carbon costs to society from the introduction and spread of a new tree-infecting Phytophthora: Thus, the overall net benefit to society from nurseries adopting best practice could be substantial.

In order to prevent and control the emergence of biosecurity threats such as vector-borne diseases of plants, it is vital to understand drivers of entry, establishment, and spatiotemporal spread, as well as the form, timing, and effectiveness of disease management strategies. An inherent challenge for policy in combatting emerging disease is the uncertainty associated with intervention planning in areas not yet affected, based on models and data from current outbreaks. Following the recent high-profile emergence of the bacterium Xylella fastidiosa in a number of European countries, we review the most pertinent epidemiological uncertainties concerning the dynamics of this bacterium in novel environments. To reduce the considerable ecological and socio-economic impacts of these outbreaks, eco-epidemiological research in a broader range of environmental conditions needs to be conducted and used to inform policy to enhance disease risk assessment, and support successful policy-making decisions. By characterizing infection pathways, we can highlight the uncertainties that surround our knowledge of this disease, drawing attention to how these are amplified when trying to predict and manage outbreaks in currently unaffected locations. To help guide future research and decision-making processes, we invited experts in different fields of plant pathology to identify data to prioritize when developing pest risk assessments. Our analysis revealed that epidemiological uncertainty is mainly driven by the large variety of hosts, vectors, and bacterial strains, leading to a range of different epidemiological characteristics further magnified by novel environmental conditions. These results offer new insights on how eco-epidemiological analyses can enhance understanding of plant disease spread and support management recommendations. [ ] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

It is widely acknowledged that a major threat to tree health biosecurity comes from trade, particularly through the importation of containerised live plants and associated growing media. Nurseries can collectively play a key role in mitigating pests and diseases through attention to their daily practices (e.g., procuring plants, storage and management). More widespread adoption of best practices in the sector could be promoted through the introduction of a UK-wide accreditation scheme. However, the success of such a scheme would depend not only on its uptake by nurseries but also on the attitudes of key consumers in the plant supply chain. To date, the perspectives of the nursery sector on the feasibility of plant biosecurity, as well as the sensitivity of these sectors to consumer opinion, have remained under-researched. Using the COM-B [Capability, Opportunity, Motivation—Behaviour] model as a framework, we draw on qualitative results to assess the appetite for a hypothetical accreditation scheme amongst UK nurseries and the capability, opportunities and motivations to enhance their biosecurity practices. Nineteen semi-structured interviews were conducted with plant nurseries and 22 with their consumers. Overall a plant health accreditation scheme should have actions that are: (1) viable within the confines of the site and supply chain; (2) affordable where the benefits of changes/improvements outweigh the costs; (3) beneficial in that they promote biosecurity; (4) attractive to consumers looking to purchase products from accredited nurseries; (5) fair and inclusive where everyone has responsibility for biosecurity; (6) transparent with the scheme involving a strong monitoring and auditing component. This study provides important insights that will feed into the development of plant biosecurity-focussed accreditation or certification.

Societal Impact Statement: The horticultural trade relies on healthy plants to flourish. However, its very nature means that it is also a key pathway for the introduction and spread of plant pests and diseases. These pests and diseases threaten horticultural stakeholders, and can also cause huge ecological and economic damage. A horticultural sector accreditation scheme, underpinned by best biosecurity practice, could help reduce these threats. Drawing on survey responses, this study examines the plant‐buying habits of UK consumers and their appetite for a horticulture accreditation scheme. We consider the necessary scope of such a scheme and outline how it could be made appealing to the plant‐buying public. Summary Movement of live plant material through the horticultural trade is a recurrent pathway for the introduction and spread of pests and diseases. An accreditation scheme underpinned by best biosecurity practice represents one approach to mitigating this risk. This research aims to determine whether an accreditation scheme would likely be supported by the public in the United Kingdom—a factor which would heavily influence its establishment and impact. Consumer attitudes and behaviours were elicited through a survey of the UK's plant‐buying public (n = 1,500). The survey explored awareness of pests and diseases, the importance of biosecurity when making plant‐buying decisions (relative to other factors), and appetite for accredited products, including plants. The sample exhibited limited awareness of plant pests and diseases and ascribed little importance to biosecurity during plant‐buying decisions. Instead, these decisions are influenced by “quality”—a factor also cited to explain consumers’ selection of (non‐horticultural) accredited goods over unaccredited varieties. Despite apparent support of a horticultural accreditation scheme's ideals, consumers expressed concern that accreditation could lead to more expensive products. Public support for a scheme aiming to safeguard the wider environment from pests and diseases is unlikely to materialize without dedicated efforts to raise awareness by key influencers such as retailers. However, an assurance of high‐quality, healthy plants would increase a scheme's appeal. Furthermore, given the diversity of sources from which plants are obtained, any would‐be scheme must encompass a range of growers and sellers if it is to be widely considered by the plant‐buying public.

The Millennium Ecosystem Assessment stresses that it is possible to manage ecosystems so as to strengthen their capacity to provide a range of goods and services. In reality, the delivery of ecosystem services reflects policy and delivery mechanisms, the environment, and the objectives of landowners and managers. Amid gradual changes to forest policy and more recent periods of austerity, the management of treescapes by locally led groups, such as Community Woodland Groups (CWGs), has become increasingly common. Through document analysis and interviews we explore the objectives and activities of British-based CWGs, and the implications these have for the delivery of ecosystem services. Additionally, we explore CWGs involvement with three types of networks and the ways in which each facilitate CWGs’ establishment, operations and ecosystem service provision. We conclude that, while CWGs are capable of delivering a range of ecosystem services, their focus is typically on: (i) cultural services for the benefit of the local community, and (ii) biodiversity. Since these foci parallel the goods and services emphasised in contemporary forest policy agendas, it is apparent that CWGs represent a promising model for woodland management. However, to realise their potential and confront management challenges, CWGs often rely on access to advice, labour, equipment and funding from across multiple networks.

The values of forests have been extensively researched by focusing on general public perspectives with different frameworks used to categorise them. Studies have also explored forest manager values; however, there is limited evidence on the values they associate with specific tree species. Understanding more about managers’ values regarding a particular species is important when considering how they make decisions and might respond to tree pests and disease threats. In this study, we explored forest managers’ values regarding oak trees and the effects of a particular pest and disease risk known as Acute Oak Decline on these. This paper outlines the results from interviews with forest managers in England and a survey of private forest managers in Britain to capture the ways in which they value the oak trees they own, manage, or influence. Forest manager types included private owners of single or multiple properties, forestry professionals, businesses, and tenants. The results show that oaks were highly valued by forest managers as an iconic cultural species in the landscape and for their timber. Veteran and ancient oak trees were considered very important, and managers were more likely to spend time and resources attempting to conserve these oaks due to their perceived cultural value. Those who had trees that were suffering from Acute Oak Decline were also more likely to spend resources on them to save the trees or try to reduce the impact of the disease. Gaining a better understanding of forest managers’ attitudes towards protecting species they value is important as it has implications for their decision-making and management behaviours. It can also help to provide relevant bodies with information on how best to develop and communicate guidance and advice on monitoring and reporting disease symptoms, as well as managing oak tree health.