Ash dieback

A highly infectious fungal disease known as ‘Ash dieback’ (previously also referred to as ‘Chalara’) is threatening to wipe out our native ash (Fraxinus excelsior), as well as most other non-native members of the ash family. Ash trees are valuable features of Devon’s landscape and are present in our native woodlands and hedgerows. Ash is one of our three main hedgerow trees, along with oak and beech, and makes up about one sixth (16%) of their shrubby growth. Both native and ornamental ash trees are present in parks and gardens.

The latest information from the Forestry Commission shows that Ash Dieback has now taken hold across much of the UK, including Devon. The disease is likely to have a major impact on Devon’s countryside, much of which is patterned by a rich network of hedges, hedgerow trees, small copses and woodland. If the Ash trees go, and evidence suggests we will lose over 90% of them, then the character of our landscapes is likely to change dramatically, with loss of trees, hedgerows and the wildlife they support.

Much has already been done to raise awareness of the disease, gather evidence and research, and try to reduce the rate of its spread. Since October 2012, the import and movement of ash seeds, plants and trees in the UK has been prohibited under the Plant Health Order 2012. Legally enforceable action can therefore be taken to control the spread of the fungus when it is found.

In 2013, Defra published its Chalara Management Plan; since then Devon County Council has been fully supporting its objectives.

Despite this, the airbourne spread of the disease has continued, and its impacts on Ash trees in our towns and countryside are now becoming noticeable.

Action in Devon

The Devon Ash Dieback Resilience Forum was established in July 2016, led by Devon County Council. The Forum is taking forward actions identified in the Devon Ash Dieback Action Plan, which was produced for Natural Devon to stimulate action. A one page summary of key facts, impacts and actions is provided.

The Devon Ash Dieback Resilience Forum is working collaboratively to raise awareness, provide advice, manage the risks posed by the disease and spearhead measures to mitigate its environmental consequences. The Forum has published freely available Guidance Notes, and the full set is available on the Devon Local Nature Partnership website.

The spread of the disease through a tree can be rapid, and replacement trees take a long time to grow. So the key message from the Devon Ash Dieback Resilience Forum is to act now to ensure Devon’s treescapes and the wildlife they support are restored and even improved for future generations.

What you can do

  • Manage risks. Check ash trees in land under your control for signs of the disease. See information on how to recognise signs of the disease in ash trees. Don’t wait until the disease makes a mature tree unsafe. If you are a landowner, you are responsible for managing the health and safety risks from dead and dying trees on your land. Monitor trees near highways and rights of way or areas with high levels of public access for signs of the disease, and if risk assessments show these as a hazard, plan careful pruning or felling. Make sure that any work to trees also manages risk of harm to wildlife – particularly legally protected species – see the guidance from the Forum. Contact Devon County Council highways if work to trees could impact on a highway. Trees in open countryside away from publicly accessible areas pose the least risk, and if the disease takes hold there are benefits of allowing nature to take its course if safe to do so. A tree that proves genetically resilient to the disease has yet to be found, but such a tree could be out there.
  • Establish more trees. Use the 3:2:1 ratio when replanting: if you remove one mature tree, plant three saplings as a replacement; if removing a semi-mature tree, plant two saplings; replace a small sapling tree with another sapling. Establish the right tree, in the right place, using the right method and make sure it has the right aftercare to ensure it grows to a beautiful mature tree. If you are not a landowner, become active in your community to identify public local green spaces for tree planting that would enhance your local environmental. Trees have multiple benefits, including supporting wildlife, reducing flood risk, filtering air pollution, enhancing the character and visual amenity of an area, and providing shade.
  • Bridge the gap. As Ash (Fraxinus sp.) can no longer be specified in planting schemes, select substitute native / locally appropriate trees that would maintain as far as possible the ecological and landscape value and benefits of Ash trees. See guidance on alternative species published in Devon Ash Dieback Resilience Forum’s Advice Note 
  • Cherish and nurture existing trees. We already have many budding saplings in Devon’s hedges waiting in the wings to be hedgerow trees. Modern hedge management techniques such as flailing can chop these down before they have a chance. Marking, physically protecting or clearly tagging candidate hedgerow trees in a hedge can help indicate to flail operators not to cut in such locations. There is also much that can be done to ensure the resilience of our existing trees and woodland. See guidance on increasing the resilience of Devon’s treescapes.
  • Keep up to date and find out more. Read the latest guidance published by the Devon Ash Dieback Resilience Forum and the Forestry Commission, including Forestry Commission Operations Note 046 dated September 2018.