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What is Ash Dieback and what are the signs?

Ash dieback is a highly destructive disease of ash trees (Fraxinus species), especially the United Kingdom’s native ash species, common ash (Fraxinus excelsior). It is also known as ‘Chalara’ and is caused by a fungus named Hymenoscyphus fraxineus (H. fraxineus).

Originating from East Asia, this pathogen has spread across Europe, posing a significant threat to ash populations. The fungus primarily infects the vascular system of ash trees, disrupting the transportation of water and nutrients, ultimately leading to the decline and death of the tree.

The devastating fungal disease has attracted significant attention due to its widespread impact on our native ash and it is crucial to recognise the signs.


How To Identify Ash Dieback

There are five key signs when looking out for this disease:

1. Crown Dieback

One of the primary indicators is the progressive dieback of the crown. This typically starts with the wilting and discoloration of leaves at the top of the tree, spreading downward. As the disease advances, affected branches will exhibit a characteristic "dieback" or death.


2. Distinctive Lesions on Bark

Infected trees display unique lesions on the bark. These lesions are often diamond-shaped and can be found on the trunk and branches and serve as a visible marker of the fungal invasion.


3. Epicormic Growth

In a survival response, ash trees affected by dieback may exhibit epicormic growth – this is where they produce new shoots and branches lower down the trunk rather than at the end of a branch. While this growth may give the appearance of recovery, it is a sign of the tree's is battling against the disease.


4. Leaves and Foliage

Affected leaves may show dark, irregular spots, which gradually expand, leading to premature leaf loss. The progression of the disease often results in a thinning canopy, further compromising the tree's ability to photosynthesize.


5. Cankers on Branches

 As the fungus infiltrates the tree’s vascular system, you could see the formation of cankers – this is dead tissue - on it’s branches which disrupt the flow of sap and weaken the structural integrity of the tree.


The Importance of Early Detection and Action

The early detection of Ash Dieback is paramount. If you have Ash trees on your property it is crucial to undertake regular inspections and monitoring them for the signs of the points mentioned above.

A prompt identification and confirmation of affected specimens can help stop the spread of the disease to healthy trees. Strategic measures can include pruning and the removal of infected material.


Talking to the experts

We have over 40 years’ experience in the management of trees and gardens, and will always provide a free consultation with expert advice on what your options are.

As professional tree surgeons, we can identify any possible Ash Dieback infections quickly and efficiently.

With continuous training, we stay up to date on all the latest treatments and can take decisive action when needed to preserve the vitality of not just the infected tree, but also the trees surrounding it.

We can give you a comprehensive plan on the best way to tackle the problem and eradicate the disease from your property.

If you have any questions or are worried about a tree on your property, talk to us today : 0800 145 52 62.



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