Ash Trees Showing Signs of Natural Resistance to Deadly Disease, Scientists Reveal

New scientific evidence suggests that ash trees are beginning to fight back against the disease that has devastated much of the British countryside.

When ash dieback first appeared in the UK in 2012, experts warned that up to 85% of ash trees could be lost. Since then, the disease has spread throughout the British Isles, causing significant damage to woodlands.

However, scientists have now discovered that ash woodlands are naturally developing greater resistance to the fungal infection.

This breakthrough offers renewed hope that these much-loved trees could continue to grace the British landscape – though this hope has come “borne out of the death of a lot of trees”, said Professor Richard Buggs of the Royal Botanic Gardens, Kew, and Queen Mary University of London.

He stressed that further support will be necessary to aid the trees’ recovery, including measures such as protecting young trees from grazing deer and selectively breeding the most resilient specimens for future planting schemes.

“We have fresh motivation to look after our ash populations, to protect them from other problems like deer browsing, and to let nature take its course and evolve trees with more resistance,” Prof Buggs said.

Ash dieback, caused by a fungus originating in Asia, was introduced to Europe around three decades ago.

Infected trees typically show signs such as withered, blackened leaves, and in many cases, the disease ultimately proves fatal.

A recent study of ash trees in a Surrey woodland revealed subtle genetic changes over time, suggesting that new saplings are becoming more resistant to the disease than earlier generations.

Richard Nichols, professor of evolutionary genetics at Queen Mary University of London, said a “tragedy for the trees has been a revelation for scientists – allowing us to show that thousands of genes are contributing to the ash trees’ fightback against the fungus”.

Rebecca Gosling of the Woodland Trust noted that ash dieback highlights the severe impact that introduced pathogens can have on native trees and the wider ecosystems that depend on them.

“The findings highlight how vital it is to support natural regeneration in woodlands, furthering our understanding of how to best manage our ash woodlands,” she said.

Scientists had previously feared that ash trees might follow the same path as elm trees, which were almost entirely wiped out by Dutch elm disease.

The loss of native ash would have posed a major threat to biodiversity.

The findings have been published in the journal Science.

 

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