What is Ash Dieback (hymenoscyphus fraxineus)

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Ash Dieback (Hymenoscyphus Fraxineus)  is an airborne fungal  disease which is likely to kill up to 90% of our Ash trees. 

Originating in Asia the fungus was introduced into Europe around 30 years ago, unfortunately there is no cure. Blowing on the wind, spores attach to the leaves penetrating the leaf, stalk and truck. After time the disease takes hold enough to block the water transport system causing the tree to die. 

There is  hope that some veteran trees will have the capacity to withstand the disease long enough to generate a resistance passing this onto their seeds.

Ash dieback can affect ash trees of all ages. Younger trees succumb to the disease quicker but in general, all affected trees will have these symptoms:

• Leaves develop dark patches in the summer.
• They then wilt and discolour to black. Leaves might shed early.
• Dieback of the shoots and leaves is visible in the summer.
• Lesions develop where branches meet the trunk. These are often diamond-shaped and dark brown.
• Inner bark looks brownish-grey under the lesions.
• New growth from previously dormant buds further down the trunk. This is known as epicormic growth and is a common response to stress in trees.

As the landowner it is your responsibility to survey for signs of ash dieback, and if it is present, to act in a structured and proportionate manner taking into account any risks to public safety.

It is now widely accepted that once more that 50%  (class 3 & class 4) of the trees canopy is affected by ash dieback it is unlikely the tree will recover  and is at considerable risk of structural failure. The tree can shed branches and limbs, or the whole tree may even collapse.

Why is this important? 

As the tree moves through the classes the structural integrity of the tree weakens.  From a tree surgery perspective as the level of the disease increases (class 3 & class 4)  so does the complexity and in many cases the cost of having work carried out. 

What we advise; 

As soon as you have identified ash dieback is present contact a tree surveyor or tree surgeon to come out and make an initial inspection and put together an action plan.   At Devon Woodman we carry out a visual inspection and risk assessment on each individual tree to assess the safest and most cost effective way to carry out any required work.