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’s also feared the disappearance of millions of trees will condemn some species 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.

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% 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 fraineus, 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 plans 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.”

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 privately owned trees likely to be removed.

The authority has said it could cost up to £40 million and has called for Government support.

As well as employing tree specialists, organisations face paying for health and safety measures to protect against falling trees and branches, legal costs linked to removing diseased trees on private property, and tree planting to replace lost specimens.

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. They include the already ‘vulnerable’ centre barred sallow moth, recognisable for its yellow wings with grey-purple stripe, and Psallus flavellus, a tiny red-brown coloured bug.

“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.

“As well as 45 species that are just found on ash trees, a further 62 are highly associated and very rarely use trees other than ash.

“There is not much we can do for the species that prefer to use ash.”

Ash is a self-seeding tree that typically survives for around 250 years. Some are particularly loved: one of Scotland’s largest and oldest native ash in Glen Lyon has a moss-covered truck measuring 6.4 metres and is estimated at up to 400 years old.

Hopes are pinned on a small number thought to have a genetic tolerance to the disease. That, however, complicates the removal of trees so genetically robust specimens are not lost.

But the impact of the disease is expected to leave many visible gaps as trees are removed: West Lothian alone has around 44,000 trees likely to be felled, many growing alongside roads and paths.

Recent research there showed a quarter are young saplings of which 87% are already badly affected, while just 4% of the semi-mature and older trees still had 75% of their crown intact.

In East Lothian, ash dieback is said to be “widespread”. Work is now beginning on the removal of 36 semi-mature trees at Millfield, home of Haddington Athletic Football Club.

NatureScot’s Duncan Stone said: “Ash dieback is significant issue in Scotland and will not only change our landscape, gardens and parks, but also our biodiversity, most notably bats, birds and specialist plants.

“As ash declines, we need to work on better protection of Scotland’s trees and woods, and growing new generations of suitable trees to replace our lost ash.”

George Anderson of the Woodland Trust Scotland, which has over 60 sites in Scotland, said it is attempting to leave as many trees as possible in the hope that some which are showing resistance to the disease will survive.

“For now, though, we have to accept a major component of the UK’s woods might vanish from huge swathes of Britain for a generation,” he added.

“In the last 30 years, more than 20 serious tree pests and diseases have arrived in the UK, and there are at least 127 tree pests and diseases considered high risk to the UK.

“By importing diseases that attack existing trees we're making this challenge even greater and damaging important habitats in the process.”

A spokesperson for the National Trust for Scotland, said it is working on an action plan.

“At this stage we can’t say what the impact of ash dieback will be on our woodlands and landscapes. Some of our sites have a lot of ash, some have very few.

“We recognise the environmental importance of ash trees as a habitat.

“We would consider carefully whether there are practical steps that can be taken to secure the future of that habitat, before moving to its removal from the landscape.”