ASH dieback was the big environmental story of 2012 - and the deadly fungus Chalara fraxinea threatening to blight our ash and so change the face of our countryside is not about to drift away in 2013.
In December, Government figures revealed that the number of infected sites (including Duns and Eyemouth) had more than doubled to 291 compared with the previous month. More than half are mature woodland areas which were most likely infected by spores blown from continental Europe or Norway in the wind, rather than by diseased young trees imported from abroad, experts said. But how can you tell if an ash is infected?
The fungus was unknown in Britain until early last year. The first case was confirmed in ash plants in a nursery in Buckinghamshire, in a consignment which had been imported from The Netherlands. Since then, more infected plants have been confirmed in nurseries in a wide range of locations in England and Scotland. Experience on the continent indicates that it kills young ash trees very quickly, while older trees tend to resist it for some time until prolonged exposure causes them to succumb as well.
Local spread, up to 10 miles, may be via wind. Over longer distances the risk of disease spread is most likely to be through the movement of diseased ash plants.
Symptoms included ead or dying tops of trees, most easily seen throughout summer; wilting leaves, most visible in spring and early summer; lesions and cankers on stems/branches/shoots, visible throughout the year; dieback of leaves with brown/black leaf stalks, seen throughout summer; fruiting bodies on fallen blacked leaf stalks, visible June to October; staining of wood under bark lesions, visible throughout the year. Check your trees as they emerge into leaf, watching for symptoms.
Once infected, trees can’t be cured. However, not all trees die of the infection. Some are likely to have genetic resistance.
The Forestry Commission advises people to check on any young trees planted in the last five years and is urging gardeners to buy disease-free stock from reputable suppliers.
To reduce spread of the disease, remove all ash leaf litter from around the trees in the autumn and winter to reduce the local source of spores the following summer. It is thought that leaf removal, possibly coupled with the lower humidity levels in parkland and urban tree environments, can significantly reduce and slow the impact of Chalara.
Safely dispose of leaves by burning, burying or composting, although in some areas and circumstances disposal might need to be undertaken by a local authority.
If you think a tree has ash dieback fill out the Forestry Commission’s ‘Tree Alert’ form on its website www.forestry.gov.uk or call the Chalara helpline on 08459 335 577.