Tree wise to ash dieback

Ash issue: A mature ash tree in Studley, Warwickshire
Ash issue: A mature ash tree in Studley, Warwickshire
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Ash dieback was the big environmental story of 2012 – and the deadly fungus Chalara fraxinea threatening to blight our ash and change the face of our countryside is not about to drift away in 2013.

In December, Government figures revealed the number of infected sites 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, rather than by diseased young trees imported from abroad, experts said. But how can you tell if the ash in your own garden is infected?

What is the situation in the UK?

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 range of locations in England and Scotland. It kills young ash trees quickly, older trees resist it for a while.

How is it carried?

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.

What are the symptoms?

Dead 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.

Is there a cure?

No. Once infected, trees can’t be cured. However, not all trees die of the infection. Some are likely to have genetic resistance.

What about newly planted ash trees?

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 suppliers.

How can I protect ash trees in my garden?

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 leaf removal can significantly reduce and slow the impact of Chalara.