Austin Brady, Head of Conservation at the Woodland Trust discusses the impacts of disease and pests on our woodlands, and how we can mitigate the risks.

It’s now just over 1 year on from the day that the devastating disease ash dieback was confirmed within the ‘wider environment’ in the UK for the first time. Up until the discovery last October at sites in Suffolk, including the Woodland Trust’s Pound Farm Woodland, it had only been found on recently planted trees. Interest and concern surrounding tree pests and diseases had been growing steadily for some time as their incidence within the UK in recent years has increased. The outbreak of ash dieback fungus, Chalara fraxinea, however has triggered a major step change. Tree health issues have regularly made national news over the past 12 months and the UK’s Department for the Environment, Food and Rural Affairs (Defra) now classes this as one of its top 4 priorities.

The growing concern and resulting action around tree pests and diseases has also been a top priority for the Woodland Trust itself. As a major landowning conservation charity managing more than 1,100 woods covering 190 square kilometres, the threat posed by a plethora of tree pests and diseases is already having a direct impact. Nearly 350 of our sites contain ancient woodland of which 70% is seminatural ancient woodland – land which has been under tree cover since at least 1600. It is the Woodland Trust’s mission to protect and create more native woodland within the UK whilst restoring areas of ancient woodland damaged through either a lack of, or inappropriate management. Pests like the Asian Longhorn Beetle (Anoplophora glabripennis) and Emerald Ash Borer (Agrilus planipennis) together with devastating pathogens such as Plane Canker (Ceratocystis platani) and ash dieback therefore pose a huge threat to the Woodland Trust’s own estate and its wider work with government, community groups and other landowners.

Upon the discovery of another pest or disease threatening our trees the first question is often what can we do? Unfortunately the UK and wider European experience usually shows us that eradication is nearly always impossible. Containment or disease ‘management’ is often the best case scenario. Can we stop these pathogens arriving in our forests? is often the next question. The UK as an island nation finds itself in a more advantageous position than most in Europe here, but again this is virtually impossible when we consider the huge volumes of live plants and associated soil, timber, biofuel and packing material being imported daily. In a globalised world where no one can afford, even if it were possible, to ‘batten down the hatches’ and close the border we need to recognise and accept the inherent risks of this trade and develop the most appropriate means of managing this risk. The European Union obviously has a large role to play here in regulating trade and setting industry standards. Its plant health regime is currently being reviewed and the proposals look very positive with an increased focus on surveillance, more stringent movement controls, greater prioritisation and a concerted effort to improve the collaboration and communication between official service, the private sector and the general public. However, the implementation of these new regulations is unlikely to happen before 2018 at the earliest. We must act now if our irreplaceable ancient woodland and relatively limited range of UK native species are to survive.

The Woodland Trust recognised the immediacy of these threats last year and swiftly implemented a three-point plan. The charity has always specified UK provenance seed for its woodland creation projects, but as of 2014 all trees will also be guaranteed to have been grown only in the UK. This immediately reduces the risk of introducing a pest or disease into the woodland as live imports of plants are one of the major ‘risk pathways’ identified by all government and stakeholder advisory groups charged with improving tree health.

An expert seminar on Tree Disease and Resilient Landscapes was hosted by the Woodland Trust and Defra in June this year. The seminar brought together 40 scientists, researchers, forest pathologists, woodland managers, professional bodies, government agencies and nature conservation NGOs to share experience and learning as well as to identify key gaps in knowledge and practice in relation to Chalara fraxinea and other threats. A summary of the seminar will shortly be published on the Woodland Trust website. As well as calls for better biosecurity at our borders and much better surveillance, detection and monitoring of pests and diseases that are current or anticipated threats, there was also much talk of improving our woodland’s ‘resilience’. Recognising the fact that we can never hope to keep out all threats and that some may arrive by natural processes the need to build resilience in our ancient and native woods is seen as the best way of safeguarding their conservation value in the long term. This will require different steps by many different parties but increasing the diversity of woodland structure, using a wider range of species and creating more genetic diversity within our woodlands will be key.

The final point of the plan is a four-year partnership project involving the government Forest Research Agency, the Food and Environment Research Agency and a fellow charity, the National Trust. ObservaTREE is a LIFE+ funded project that will develop an early warning system for tree pests and diseases by engaging citizen scientists with leading tree health organisations to help detect and verify pests and diseases in order to avoid their spread and minimise woodland loss. Through the use of expert volunteers, trained by the Woodland Trust, the project will assist scientists with the investigation and filtering of tree health incidents reported by the public. This will enable tree health scientists to focus on the reports of greatest significance. The processes and experiences gained through this project will be shared with counterparts across Europe in an effort to ensure best practice is shared and the necessary international approach to tackling tree pests and disease is supported. This pan-European approach, shared with other initiatives such as FRAXBACK, will be essential if we are to learn from each other in order to ensure our forests can survive the current and future pest and disease threats.


Austin Brady

Head of Conservation

Woodland Trust

Tel: +44 (0)1476 581111


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