Tree owners have been warned of a very short window to check for the potentially deadly ash dieback disease before it is too late.
Experts say that by Sunday most of the ash trees’ leaves in the north of England will have fallen from their branches.
They have issued an urgent message calling on tree owners and landowners to get out into the woods to test before this happens.
Dorothy Fairburn, of the Country Land and Business Association, said: “Cases need to be identified within the next 48 hours before any more leaves fall.
“Once the leaves have gone, the fungus is much harder to detect.”
More than 100,000 trees have already been destroyed in the UK to stop the spread of the disease, particularly in East Anglia which has been particularly badly affected.
The CLA is now working with the Forestry Commission to compile a spotter’s guide to help woodland owners identify the symptoms of the ash virus Chalara fraxinea.
The groups will then be able to record the spread of the disease on a national database.
Dorothy Fairburn said: “The Environment Secretary has specifically asked CLA members to get out this weekend to check on whether their ash trees have Chalara.
“He wants to get a more accurate feel of how widespread the problem is.”
The Forestry Commission’s guide says that the most obvious symptoms are blackened leaves and necrotic lesions on the twigs, branches and main stem.
Tim Rollinson, Forestry Commission director general, said: “We all take the threat to our ash trees extremely seriously and would like to thank the CLA and its members for all their efforts and we will continue to work closely with them.”
Owners can check if their trees are showing signs of ash dieback by following the advice at www.forestry.gov.uk/chalara and downloading and completing a survey form from http://www.cla.org.uk/ty/nDYcRg/.