Chalara Dieback of Ash

Chalara dieback of ash is a serious disease of ash trees caused by a fungus called Chalara fraxinea (C. fraxinea).

The disease causes leaf loss and crown dieback in affected trees, and it can lead to tree death. For more information and advice about the symptoms and spread of Chalara through Europe and into the UK please see the Forestry Commission website.


What should I do if I think my ash trees have the disease?

Check the Forestry Commission web site for identification pictures and videos and report it to the Forestry Commission.


Within Welwyn Hatfield

The Forestry Commission has confirmed that chalara is present within Welwyn Hatfield.

The Council will follow the government's latest advice. We will:

  • Be vigilant for symptoms of the disease of Council maintained trees and report them to the Forestry Commission if necessary.
  • Keep up to date with the latest outbreak information and re-appraise the situation as necessary.
  • Accept the use of alternative plant species on planning applications.