PuRpOsE: PRotecting Oak Ecosystems: understanding and forecasting causes and consequences, management for future climates

Oaks are iconic trees in the UK and throughout much of Europe. Our two native oaks are species that members of the public recognise and which have considerable cultural, economic and biodiversity value. Indeed, we do not yet have the knowledge to understand health threats to oak or prepare for the likely reactions of wider stakeholders and the public. Pedunculate and sessile oak are widespread in the UK. Recently there has been an increase in non-native invasive pathogens and pests establishing in the UK and causing damage and/or death to many tree species. Oaks are under threat from several new pests and diseases, including Oak Processionary Moth (OPM) and Acute Oak Decline (AOD). For some of these, we do not yet understand how they cause decline in oak health and often there is no current treatment other than sanitation felling. We therefore urgently need to identify why trees are becoming more susceptible to pests and diseases and to develop management methods that would help reduce oak susceptibility. A decline in tree health and the potential loss or decline of oaks will have impacts on the plants, animals and humans that use oak trees and/or oak woods. Thus we need to assess the impacts of oak pests and diseases on the wider environment and how we can mitigate the impacts.

PuRpOsE is a research project to PRotect Oak Ecosystems through understanding and forecasting causes and consequences, and adaptation management for future climate projections. Our work to understand interactions between pests, diseases, environments and humans is led by a group of world-leading scientists who will address these issues. One focus of our work is AOD, but the outcomes of this study will provide valuable validation of approaches to other diseases and pests, such as OPM. Our work will increase our understanding of the causes of oak decline (particularly AOD) and determine the physiological and other phenotypic changes brought on by AOD infections and their impact on associated communities in the rhizosphere. We will produce risk maps and stress maps to identify climatic/soil regions where oaks are most at risk from AOD and from other pests and diseases, respectively. We will conduct a horizon scanning exercise, framed within the context of projected future climates, to identify potential new threats to oak health, the risk criteria and management options. Combining knowledge from risk mapping, stress mapping and horizon scanning, we will assess how forest management can reduce oak decline. Mitigation might necessitate replacement planting. Within PuRpOsE we assess tree species that could replace the function oaks have in the landscape in terms of biodiversity and ecosystem functions and the services associated with oak woodlands. Armed with the outputs of this research, we will identify adaptation strategies to reduce the impacts on biodiversity and ecosystem services such as carbon storage and water quality, engaging stakeholders in developing dynamic adaptive pathways for management and recreation from the loss of oak. Underpinning all of this work is a strong team commitment to working collaboratively across the natural and social sciences to understand tree health issues as involving pests and pathogens, hosts, environments and humans. The project aims to develop a common language to provide improved knowledge and understanding of health threats to native oaks, now and into the projected climate futures to decision-makers involved in tree health policy regulation, trade and forest policy and practice.

In the UK, Quercus robur and Q. petraea are under threat from new diseases including Acute Oak Decline (AOD). The PuRpOsE (PRotect Oak Ecosystems) project will improve knowledge and understanding of interactions between pests and diseases, environments and humans related to the health threats to native oaks now and going forward through projected climate futures. We will identify the wider impacts of oak decline on biodiversity, ecosystem function and services, and interactions between institutional stakeholders, to identify policy and practice that will reduce or mitigate these impacts. We will deploy state of the art methodology to identify biotic and abiotic factors that affect tree susceptibility and disease development and determine phenotypic changes brought on by AOD infections. Horizon scanning using expert opinion and novel climate matching tools will identify potential future oak pests/pathogens. We will screen current and new oak silvicultural systems and use existing trials of climate matched provenances and species diversity plots. Together with key stakeholders, we will use the assimilated project knowledge to investigate adaptive management pathways to prevent/slow down oak pest and pathogen impacts. Applying theoretical and methodological innovations in the social sciences relating to tree health issues and complex stakeholder interactions, we will consider how disease 'stories' emerge and how the enthusiasm of actors involved in AOD can help develop collaborative strategies for managing and living with AOD. Working with stakeholders throughout the project we will enable:
1. Policy makers in charge of natural resource planning to understand the risk of oak decline and provide them with evidence-based knowledge to change policies appropriately
2. Managers to feel confident in preparing for change and to start managing their woodlands appropriately
3. Stakeholders to be less averse to the changes required to mitigate the impacts of oak decline.

The impact we aim to generate will stem from our interdisciplinary research including state-of-the-art microbiome and metabolomic studies coupled with applied and practical forest ecology and social science work to establish human approaches to recognising and managing oak disease. Specifically, we will seek to: 1) influence decision-makers in forest policy and practice (e.g. Scottish Natural Heritage, Natural England, Natural Resources Wales, Woodland Trust, Forestry Commission England and Scotland, Environment Agency, Scottish Environmental Protection Agency, National Trust, Fera, Defra, Confederation of Forest Industries, Institute of Chartered Foresters, City Councils, nursery trade and community woodland groups) to improve their understanding of oak related pests and diseases and the threats posed to the wider ecosystem; 2) provide policymakers in charge of natural resource planning with the evidence to change policies appropriately; 3) instil confidence in forest managers to implement the management required to maintain oak ecosystem health; 4) prepare stakeholders for a potential loss, or major decline of oak. We can only do this by understanding if trees are experiencing stress that makes them more susceptible to disease (WP1 & 2) with knock on effects to ecosystem services (WP3) to use these data to develop indicators of threat (WP1) and in combination with tree surveys to develop a risk map (WP2) for future management purposes. Underpinning the project is WP4, which addresses the need to effectively understand the different human approaches to understanding how pests and diseases spread and how different scientific approaches might drive different management policies. Throughout the project's implementation we will deliberatively engage with key stakeholders in a co-learning process, specifically working together with individuals from our case study sites dispersed across the UK, as well as with local, regional and national organisations, for example through our Project Advisory Group.