Ash dieback, also known as Hymenoscyphus fraxineus, comes from Asia and is highly infectious.
Trees and woods which inspired the likes of Beatrix Potter and John Constable could be lost due to a surge in a disease affecting ash, the National Trust has warned.
The conservation charity said it faces having to cut down 40,000 infected trees – a new record – thanks to a fungus called ash dieback.
The National Trust has been felling around 4,000-5,000 annually in recent years, mostly thanks to the fungus.
This year’s record numbers have been blamed on climate change and the UK having one of the warmest and driest springs on record.
The increased temperatures are putting trees under stress and making them more susceptible to the disease, the trust said.
The charity also blamed lockdown for preventing rangers from carrying out vital maintenance work on the affected trees.
It comes as a study found woodland cover in some of England’s national parks is lower than it is in major cities.
The survey of 10 English national parks, which would once have been filled with temperate rainforest and wild woods, found just 15% of these landscapes are now wooded.
The Yorkshire Dales, the Peak District and Dartmoor were found to have less tree cover than cities like London, Leeds and Sheffield.
The group said the findings show the amount of woodland cover in these areas could be more than doubled without harming other important habitat and land.
The findings come after the government announced on Wednesday it would be protecting an extra 400,000 hectares of land in England, bringing the total amount protected up to 30% by 2030 in a bid to reverse declines in wildlife and habitats.
Ash trees are the third most common species in the UK and vital for woodland ecosystems.
Ash dieback, also known as Hymenoscyphus fraxineus, comes from Asia and is highly infectious. It was first recorded in the UK in 2012.
It blocks the tree’s water systems and causes leaves to wilt, shoots to die back, lesions on branches and eventually dies
Set to kill between 75-95% of the UK’s ash trees, the disease is expected to wipe out around 2.5 million trees on National Trust land alone, with hundreds of thousands having to be felled to ensure public safety.
The cost of cutting down so many trees this year is £2 million.
Beautiful landscapes under threat include the Cotswolds, where more than 7,000 trees will have to be felled in the coming year.
Woodlands around the home of painter John Constable in Flatford, Suffolk, are also under threat, while dozens of trees will have to be felled this year in Borrowdale in the Lake District, which the artist travelled to paint.
Elsewhere in the Lake District, sites that inspired the work of children’s author Beatrix Potter, including Troutbeck Farm near Ambleside which she managed in 1923 and High Oxen Fell, near Coniston, are also at risk from ash dieback.
The National Trust is warning that other woodlands, including the ravine woods of the White Peak in Derbyshire, which are 80% ash, and in the Yorkshire Dales, will change beyond recognition because of the disease.
National tree and woodland adviser Luke Barley said: “Ash dieback is a catastrophe for nature. Our landscapes and woodlands are irrevocably changing before our eyes, and this year’s combination of a dry spring and late frost may have dramatically sped up the spread and severity of ash dieback.
“Ash trees like those at Beatrix Potter’s Troutbeck Park Farm are some of our most culturally significant trees and have stood for hundreds of years but will now be lost forever.
“As well as the cultural impact of losing these historic sites, there are also implications for climate change as less carbon is sequestered, homes for wildlife are being removed and people’s access to nature is being diminished.”
He also warned: “The issue of ash dieback is nothing new, but the speed at which it is spreading seems to have been exacerbated due to the weather, and the time and expense necessary to tackle it contributes to the perfect storm we are witnessing.”
The charity, which needs to save £100 million as a result of the pandemic, is making a direct appeal to the public to replace lost woodland by donating to the Everyone Needs Nature campaign via its website.