Ashes to ashes Thousands of trees felled due to deadly fungus
Scotland’s mighty and ubiquitous ash trees are under threat – leaving a £180m bill for taxpayers and many species without a home
STANDING up to 40 metres tall, their leafy canopies have been a familiar feature of the landscape for hundreds of years, providing a home for an array of species.
However, the impressive sight of towering ash trees will soon be a thing of the past – with up to 75 million likely to be completely wiped out in Scotland over the next two decades, leaving a £180 million bill in their wake.
Ash dieback, formally known as “chalara”, was first identified in England a decade ago. It is said to have become particularly noticeable in Scotland over the past two years.
Local authorities are now being urged to draw up action plans to tackle dying trees, with warnings of risks for wildlife, flooding and human safety.
Diseased ash trees become fragile, creating a risk of branches overlooking paths and roads suddenly snapping.
It is also feared the disappearance of millions of trees will condemn some wildlife that rely on them, with a knock-on impact on hundreds of species such as certain bats, birds, insects, mosses, fungi, and lichens.
And as well as leaving gaping holes where much-loved trees have stood for generations, the loss brings implications for flooding, air quality, carbon storage, and sequestration.
Official warning
THE Tree Council has now drawn up guidelines on how to deal with the issue, with a warning that ash dieback is now firmly established across large areas of Scotland and “likely to be present over far more of the UK than has been officially reported”.
It urges local authorities and property owners to create action plans, adding: “Ash tree failures, including branch shedding and instability, could translate into an increase in the number of incidents where people or property are harmed/damaged and hence a potential increase in insurance claims.
“The stark reality is that up to 90 per cent of our ash trees are likely to be significantly affected by ash dieback within the next decade. “Scotland cannot afford to be passive and let ash dieback run its course without careful thought, vision and proactive intervention.
“The stakes are too high.”
Ash dieback is caused by a wind-born fungus, Hymenoscyphus fraxineus, which arrived in the UK on imported trees. In Edinburgh, where the council has recently published an ash dieback action plan, there are at least 44,000 ash trees in local authority and private ownership, and around 30,000 more in its Millennium Woodlands, including Craigmillar Castle Park. The council is planning annual surveys of roads, footpaths and sites including schools, civic buildings, sheltered housing, and cemeteries in search for diseased trees.
A recent report to councillors warned “many thousands” of trees would be lost, creating “unavoidable financial pressure.”
Dear green place
IN Glasgow, council tree officers have reported a “noticeable increase” in ash dieback in the city over the past two years.
Around 4,500 council-owned trees are to be felled annually over the next seven years, with the same number of privatelyowned trees likely to be removed. The authority has said it could cost up to £40 million and has called for Government support.
Felling affected trees is treacherous and costly: diseased ash trees often need to be removed using mechanical equipment and with a range of safety measures in place.
The cost of felling just one tree has been estimated at upwards of £800, but that could soar as demand rises for arborists’ services.
Homeowners who have ash trees growing in their gardens also face potential liability issues should a diseased ash collapse.
As well as altering the landscape, new research by The James Hutton Institute in Aberdeen reveals 107 species that rely heavily on ash trees will be put at risk.
Of those, 45 species – 11 fungi, 30 invertebrates and 4 lichens – depend entirely on ash trees.
Scotland cannot afford to be passive and let ash dieback run its course without careful thought, vision and proactive intervention. The stakes are too high
“Until now we didn’t know how many species might be affected,” said Dr Ruth Mitchell, who worked on the UK-wide study. “We found 955 species that are found on ash.”
Ash is a self-seeding tree that typically survives for about 250 years. Some are particularly loved: one of Scotland’s largest and oldest native ash trees, in Glen Lyon, has a moss-covered truck measuring 6.4 metres and is estimated to be up to 400 years old.