Ash is one of Ireland’s most widespread native trees. It is found in 91% of native woodland habitats and supports a variety of wildlife. It is used as firewood, in furniture making, but perhaps best known for its use in making Hurleys. Unfortunately, recent years has seen a decline in this native tree due to a disease called Ash Dieback. Read on to find out more about the disease, how you can identify it and what you should do if you discover it.

Nature photography of Ash tree in woodland habitats
Ash (Fraxinus excelsior) (Source:

What is Ash Dieback?

Ash Dieback is a disease caused by a fungus known as Hymenoscyphus fraxineus, affecting Ash trees. The disease affects trees of all ages. It can be particularly detrimental to younger trees while older trees can survive many years with the disease. It is thought to have originated in Asia. In Ireland, the first confirmed case of Ash Dieback was made on the 12th of October 2012 in Co. Leitrim on a forestry plantation. The trees had been imported from Continental Europe in 2009. All the trees on this plantation had to be destroyed.

How does Ash Dieback disease spread?

During the summer, the spores of the fungi from the leaves which have fallen the previous year travel in the air and land on the leaves of a healthy tree. The fungi grow into the leaf, eventually making its way into the twigs, branches, and the stems. The leaves will remain on the tree but eventually, begin to wilt and then blacken. Because the disease is spread by air, surrounding trees become infected easily. Each year the spores can travel many kilometres from the source.

Ash dieback in Wildlife Ireland and Irish woodland habitats
Ash Dieback in Ireland in 2017

How to Recognise Ash Dieback in Woodland Habitats

  • Leaves may be wilting and blackened. Although this can also occur due to frost in late spring. If you see these symptoms between July- September, then it is probably due to Ash Dieback.
  • Branches may have diamond or angular shapes of dead bark and lesions.
  • Stems may be discoloured with a brownish orangish colour

If you think your Ash trees have Ash Dieback…

If you think a tree/trees may be infected, it is very important that you report it to the Forest Protection Section of the Forest Service. This will help to stop the spread of the disease.

  • Never send samples in the post, as you may be just transporting the disease to another area.
  • Send close-up photos of the affected area of the tree.
  • Do not remove any plant material from the site, remove any debris from your clothes and shoes to minimise transportation of disease.

The forestry inspector may need to take samples and will advise you on what steps to take next.

What is currently been done?

Research is currently been undertaken to find out more about the disease. A small number of trees are exhibiting a natural tolerance to the disease. A project is already taking place to build up a gene bank of Ash trees with a goal to produce trees that are tolerant of Ash Dieback.


Written by Mary Moroney





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Caretaker of the Cork Nature Network website