Chalara dieback, an incurable killer of ash trees continues its quick march across the UK. Only first detected in 2012, there are now infected trees right across England and Wales and also into northern Scotland.
It is a national and international tragedy that England, Wales and Scotland will lose all their ash trees. Apart from the huge change it will bring to the UK’s landscapes as the ash trees disappear, there is the psychological blow to a culture that has long celebrated the ash tree in poetry and song. It’s so sad to think that within a few years there will probably be no “Ash Grove‘** anywhere in Wales, England or Scotland. And of course there’s the animals and microfauna that rely on ash trees for food and habitat.
Coming after the near extinction of English elms from Dutch elm disease in the late 20th century, one starts to wonder how many other types of trees will one day also be doomed, victims of the too-free movement of potentially infected tree stock, our love of mass planting, a general loss of biodiversity, and the use of cloned material for plant production, rather than seed.
You can see the current extent of UK chalara reports on the Forestry Commission website map, showing there are just a few pockets of Cornwall, and the Scottish Highlands and islands that are still chalara free.
Symptoms of the fungal disease called chalara dieback of ash (Hymenoscyphus fraxinus) include small spots on the bark which become larger fungal cankers, followed by drooping, blackened leaves, stained bark and then tree death. It was first discovered in Poland in the early 1990s and has since spread across Europe. Fraxinus excelsior and its cultivars are the main species affected.
Studies on natural populations of European ash trees have found that a tiny percentage do have natural resistance to the fungus and there is also some promising research on how applying biochar can improve resistance to the disease.
** The Ash Grove is a traditional Welsh folk song learned by millions of school children:
Down yonder green valley, where streamlets meander,
When twilight is fading I pensively rove
Or at the bright noontide in solitude wander,
Amid the dark shades of the lonely ash grove;
‘T was there, while the blackbird was cheerfully singing,
I first met my dear one, the joy of my heart!
Around us for gladness the bluebells were ringing,
Ah! then little thought I how soon we should part.
Still glows the bright sunshine o’er valley and mountain,
Still warbles the blackbird its note from the tree;
Still trembles the moonbeam on streamlet and fountain,
But what are the beauties of nature to me?
With sorrow, deep sorrow, my bosom is laden,
All day I go mourning in search of my love;
Ye echoes, oh, tell me, where is the sweet maiden?
“She sleeps, ‘neath the green turf down by the ash grove.”