Wednesday, 5 December 2012
I have received a number of enquiries about ash die-back (Chalara fraxinea) the disease which has been so much in the news. Ash leaves often turn black in frost or very cold weather and this looked remarkably like the symptoms of the disease.
As far as I know there is no confirmed occurrence of the disease in this area. It will be hard to recognise now that the leaves are off the ash trees and there is no danger of it spreading until the spores are released in mid summer - July and August. So for now there is nothing to be done by the general public.
However I thought this video from the Forestry Commission might be of interest. It shows how to recognise the disease.
There is another rather re-assuring video by Markus Eichhorn of Nottingham Science. Maybe it's not all bad.
The fungus overwinters on the woodland floor in the fallen leafstalks of infected trees, which it turns black. So sweeping up the leaves and burning them can slow the spread of the disease. But really it seems to me that we can do little about it. Once the 90% of affected trees (if we are anything like Denmark) have gone, then hopefully the 10% of resistant trees will start to re-colonise the woods. Meanwhile the landscape will adapt.