Ash trees face threat of ‘elimination’

Twin plagues will eradicate common native tree, say scientists

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Britain’s third most common tree species will soon be destroyed, in a mass extinction that mirrors the devastating effects of Dutch elm disease, according to new research published in the Journal of Ecology.

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The largest ever survey of the ash tree predicts that our 125 million ash trees will succumb to twin plagues.

The first, a fungal disease known as ash dieback or chalara, is already killing thousands of trees in the UK. It alone has the potential to kill up to 95% of Britain’s ash trees.

The second threat is a beetle called the emerald ash borer, whose larvae are currently devastating Russia’s ash trees.

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Photo credit: iStock

The beetle has yet to arrive in the UK, but Dr Peter Thomas of Keele University, who led the research, says that’s ‘only a matter of time’.

Any trees that prove resistant to Ash dieback fungus are likely to fall victim to the beetle, said Thomas.

Together, the two scourges made it “likely that almost all ash trees in Europe will be wiped out”.

The extinction would permanently change the look of the British countryside, added Thomas.

It would also endanger more than 100 species of lichen, fungi and insects that depend on the ash tree.

According to Forestry Commission research, there are 125.9 million ash trees in Britain. That’s an estimated 11% of broadleaf trees – only oak and birch are more common.

Sixty million elms are thought to have perished in two outbreaks of Dutch elm disease, in the 1920s and again from the 1960s.

Ash dieback : tree killer

• Caused by a fungus called Hymenoscyphus fraxineus.

• First identified in the UK on a consignment of saplings imported by a Buckinghamshire nursery in 2012.

• It is usually fatal, first causing leaf loss, crown dieback and bark lesions.

• Now officially widespread in the UK.

• The fungus was previously called Chalara fraxinea, hence the common use of the name ‘chalara’ for the disease.

Emerald ash borer: prepare for invasion

• A bright green beetle, 7.5mm to 13.5mm long.

• Endemic in Asia.

• Spreading west through Russia at a rate of 25 miles a year.

• Reports indicate the beetles have now reached Sweden.

• Most ash trees die within 2-3 years of emerald ash borer attack

Ash trees: the facts

• The European ash, or Fraxinus excelsior, reaches a height of up to 35m

• Healthy trees may live up to 400 years

• Easily identified though its black buds and clusters of seeds, especially in winter

• A fast-growing hardwood, strong and flexible, useful as making tools, or burning as fuel.

• Known as the ‘Tree of Life’ in In Viking mythology. In Britain folklore, ash is known as a healing tree. 

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• More details from BBC News.