What Is Ash Dieback?
Ash dieback is a disease caused by infection with the fungus now known as Hymenoscyphus fraxineus, which is particularly lethal to the European or common ash (Fraxinus Excelsior). It poses a major threat to woodland and amenity trees alike, and is predicted to wipe out approximately 80% of Ash trees across the UK.
How To Recognise Ash Dieback
Ash dieback is easier to spot during the summer, when the tree is in leaf, however a professional arborist should be able to identify it at any time of year. An infected tree will exhibit some or all of the following symptoms:
- Crown may appear sparsely foliated and leaves might shed early
- Leaves develop dark blotches in summer then wilt and discolour to black
- First twigs, then branches and whole limbs start to die back
- Dark brown necrotic lesions develop close to branch unions. It is of particular concern if these appear at the base of major limbs or the trunk
- Previously dormant buds on the trunk and limbs produce epicormic shoots, which themselves start to die back, often turning biscuit brown and brittle
How Can We Help With Ash Dieback?
If you suspect that a tree on your property has ash dieback, we would recommend that it be inspected by one of our professional arborists to assess the risks and propose a management strategy. This will be informed by a number of factors including; how advanced the infection is, the position of the tree and its overall health and vigour. We will also take into account client related factors such as sentimental attachment and budget.
Whilst many trees with ash dieback will need to be removed for safety reasons, we do encourage clients to retain trees where it is safe and appropriate to do so. This may be because the tree is in a rarely frequented area and poses limited risk but more often is an attempt to preserve trees that exhibit some natural resilience to the infection – as these may hold the key to fighting the disease in the future. In the case of the latter, a more conservative approach may be called for, such as removal of deadwood, weight reduction of extended limbs or even installation of a dynamic bracing system if appropriate.
What Can You Do?
If you find a suspected case of ash dieback, you can report it via “TreeAlert”.
Because trees infected with ash dieback can become structurally unsound, they can pose a risk of injury or death, as well as property damage. It is therefore important for all tree owners to understand their legal responsibilities. More information can be found in this “Guide from the tree council”
In terms of limiting the spread of ash dieback, one option is to collect and dispose of fallen leaves as this is where the fungus that causes ash dieback over winters. It is important not to move these leaves far from their original location as this could further spread the disease. They should be either burnt or preferably composted under a 10cm layer of soil or a 15-30cm layer of other plant material. They should then be left undisturbed for a minimum of 12 months. This process should reduce the number of spores in the air and the risk of further infection the following year.