Ash die-back and other tree health issues
Tree health: what to look
|Ash leaves wilt and their midrib and stalk turn brown (looks like potato blight)||Ash dieback / chalara|
|Dark weeping patches on tree stems, crown deterioration||Acute oak decline|
|No tree leaves or ivy to about chest height; little understory vegetation; browsing of new shoots on freshly coppiced trees||Too many deer|
Chalara is spread by spores carried on the wind, and by planting young infected trees. Some trees have a natural resistance to chalara. So…
- Don’t plant new ash trees
- Don’t remove existing mature ash trees
- As chalara spreads, try to identify resistant trees: they will act as seed sources for future generations of resistant ash
- Find out more on www.forestry.gov.uk/chalara.
Government’s chalara management plan of March 2013 is at www.defra.gov.uk/publications/files/pb13936-chalara-management-plan-201303.pdf
Can diseased trees be used as woodfuel?
- If they have a fungal disease (like chalara), yes but the wood should be transported only locally. Leaves and brash should be burned on site to prevent the spread of disease, but if/when the disease becomes endemic it is not worth the effort
- If they have an insect-borne disease, yes but IF THE WOOD IS TRANSPORTED IT SHOULD NOT BE STORED – it should be used immediately – as living grubs may otherwise be moved from an infected to a pest-free area, mature into adults, and start a new infestation
- Unless you know that you are in a disease-free or disease-endemic area, machinery that has been used on diseased trees should be cleaned with methylated spirits to avoid spreading the disease. If you are pruning, you may want to sterilise between trees, depending on circumstances.
For more advice on dealing with chalara, over-browsing by deer and other tree health problems, contact David Rees, manager of the Oxfordshire Woodland Project, 01865 815427, David.Rees@oxfordshire.gov.uk.