Some of Britain’s most beautiful woodlands are threatened by a clutch of tree diseases that are growing in severity, the National Trust has warned.
Tarn Hows, a popular Lake District beauty spot, is being blighted by Phytophthora ramorum, a fungus-like pathogen that attacks larch. Coniston, Wasdale, Langdale and Crummock are also being badly hit by the disease.
The largest woodland affected is Holme Wood, above Loweswater in the Lake District, three quarters of which will lose trees under rules that require all larch to be felled within 100 metres of one that becomes infected.
The trust expects to fell 5,000 larch due to the disease in the year to April next year, including many large trees planted more than 100 years ago.
Larch is commonly grown for timber but also to add texture and colour to the landscape as a deciduous conifer. It causes much less shading than conifers such as Sitka spruce, meaning more wildlife can live beneath it.
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The trust also expects to fell at least 30,000 ash trees this winter due to dieback, equalling last year’s record high due to the disease. It said that between 75 and 95 per cent of all ash trees were likely to be lost to ash dieback over the next 20 to 30 years.
Dieback is thought to have arrived on imported ash trees some years before it was identified in Britain in 2012.
Other pests and diseases not yet affecting the trust’s land but which it fears could do so in future include Phytophthora pluvialis, which affects several species including Douglas fir, western hemlock, tanoak and pine. It was found in September near the National Trust’s Lanhydrock estate in Cornwall, the first time it had been identified in Europe. It has since been discovered in Devon, Cumbria and northwest Scotland.
The eight-toothed European spruce bark beetle, which affects spruce species and was found in Kent and East Sussex this summer, is also a concern.
Some trees blown down by Storm Arwen on trust land last month were found to have been almost hollowed out due to disease. Tree experts at the trust say that milder, wetter winters expected due to climate change may create ideal conditions for diseases.
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John Deakin, the trust’s head of trees, said droughts and storms were causing stress to trees, reducing their ability to resist pathogens. “This could have a catastrophic impact on our countryside and for nature, as homes for wildlife are depleted,” he said, adding that many native species could vanish.
