Ash to ashes as disease hits

I WAS doing a guided walk through a forest the other day and several people asked me about the ash die-back disease and the threat it poses to Irish ash trees.

The news is not good. The disease is caused by a new fungus, Chalara fraxinea, which was only named in 2006. It has been spreading rapidly westwards across Europe and causing havoc. It was identified in Ireland on Oct 12 last year in an ash plantation in Co Leitrim. On May 17 this year, the Department of Agriculture published a list and a map, confirming it at many locations in all four provinces.

All the confirmed locations are ash plantations, tree nurseries, garden centres or private gardens. But these are the places where scientists have been looking. The spores of the fungus spread on the wind and it is inevitable that wild hedgerow and woodland trees are infected.

We have a small tree flora on this island and the ash is far more important here, both commercially and ecologically, than it is in any other part of Europe. In Denmark, less than 1% of ash trees remain unaffected. Young trees die instantly. Older trees resist infection for longer. However, in Poland, the first European country to report the disease, between 10% and 25% of trees are showing “some degree of natural immunity”.

The official response to the disease, in this country, has been restriction of the importation of live ash saplings and dead ash timber, and a programme of ‘sanitation felling’ where the disease is present. This approach has been controversial in Britain. Richard Mabey, the veteran English ecologist and author, recently wrote: “Sanitation felling, which was talked about in the first wave of panic, would have been worse than useless, doing the disease’s work for it, eliminating potentially resistant trees and throwing more dormant spores into circulation.”

He argues for a more laissez-faire attitude. Perhaps we should be debating the point in this country. We should be familiarising ourselves with the symptoms of the disease — there are many websites with full descriptions — and should be keeping a close eye on our local ash trees.