If you consider that your Ash tree is suffering from Ash dieback, please follow the guidance below.
The Forestry Commission/DEFRA have a dedicated helpline to receive all public reports of Ash Dieback sightings:
Helpline: 0845 933 5577
If you wish to e-mail details, please include your name and address, location of the tree and if possible photographs of the tree (this will help the forestry commission to get a quicker diagnosis). E-mail: firstname.lastname@example.org
This condition can kill a tree in as little as four or five years. It has been found affecting hundreds of trees across central and south-east England and parts of Wales, Symptoms include dark fluid bleeding from splits in the bark on tree trunks, and as affected trees approach death there is a notable deterioration of the canopy, or tree tops, and 'dieback' of the branches
The Forestry Commission has information relating to Acute oak decline including area of outbreak, symptoms, advice and guidance and reporting suspected cases on their website
Forestry Commission - Acute oak decline.