Ash Dieback – what is it and what are its implications?

Ash trees are found in woodland and non-woodland settings, in both urban and rural landscapes. They constitute 12% of Great Britain’s broadleaved woodland and are also frequent in parks, gardens, hedgerows, roadside margins and close to watercourses. As well as being an attractive part of the landscape, ash provides a number of other benefits including production of timber, maintenance of water resources and the provision of habitat for other species. Ash dieback is a fungal disease affecting the common ash tree (Fraxinus excelsior) and other Fraxinus species. It is caused by a fungus called Hymenoscyphus fraxineus (formerly known as Chalara fraxinea) which is native to eastern Asia.

The disease has the potential to cause significant damage to the UK’s ash population. It has already caused widespread damage to ash populations in continental Europe. It can kill young ash trees quite quickly. Older trees can resist infection for some time until prolonged exposure, or an attack from a secondary pest or pathogen, eventually causes the tree to succumb.

The attached documents offer an introduction to ash dieback in our countryside.

Chalara leaflet

Symptoms associated with Chalara dieback of ash

Managing Ash Dieback in England