British landscapes will be devastated by the collapse of the ash. In the long term, resistant strains may pull through
The ash is one of Britain’s most recognisable and common trees. Tall and elegantly canopied, it is also one of its most beautiful, with its pale, feathered leaves and its fruits – its “ash keys” – hanging from its branches like real bunches of keys dangling from a caretaker’s belt. The late emergence of the leaves of ash trees allows species such as dog violet and mercury to thrive beneath them. Woodpeckers, owls and nuthatches nest in them. Lichens, moss and liverworts grow happily on them. Friendly fungi – such as the marvellously named King Alfred’s cakes – flourish upon them.
The National Trust reports that 30,000 ash trees on its land will have been felled this year owing to ash dieback. “Dieback” sounds like a gentle, seasonal withdrawal. In fact, ash dieback is a devastating disease caused by a fungus, Hymenoscyphus fraxineus, likely to have been carried into the UK on imported ash saplings in the early part of this century. A ban came on such imports in 2012 – too late to do much but slow the fungus’s spread. When affected by the gradually developing ailment, the leaves of the ash wither and blacken, and lesions develop on the branches; eventually the tree dies.
