HUNDREDS of thousands of larch are to be cut down on the Isle of Arran to slow the spread of a killer tree disease.

Phytophthora ramorum is a fungus-like pathogen that spreads by generating spores and has had its most significant impacts on larch across south west Scotland, where the weather is known to be favourable for infection and spread.

It was first found in Scotland in 2002 and there is no known cure. The only way to slow the rate of spread is to fell the infected trees and those surrounding them.

Phytophthora ramorum can be spread in mud or needles stuck to footwear and tyres on bicycles, buggies, machines and vehicles.

And public body Forestry and Land Scotland (FLS) has been advising the public to ensure footwear, bikes, kit and dogs’ paws are always clean before and after visiting any woodland.

Arran is one of several areas in the south and west of Scotland where the scale of infections has increased this year.

Almost half a million trees are to be felled on Arran, bringing "substantial changes to some well-loved landscapes".

The work is due to start next month and will take several years to complete.

But it is not just Arran.

Scottish Forestry, the regulator for forestry in Scotland, conducts bi-annual helicopter surveillance and associated ground surveys of larch to monitor the spread of Phytophthora ramorum.

Some 80 suspected sites in Cowal, a peninsula in Argyll and Bute that extends into the Firth of Clyde Felling operations and site closures are ongoing throughout 2020-2021 in order to remove affected trees and reduce the risk of spread to other woodlands in Cowal and elsewhere in Argyll.

Felling operations mean certain areas and paths throughout Corlarach Forest, Benmore Forest, Puck's Glen and Kilmun Arboretum will be closed to the public for safety reasons.

FLS said it was working on plans for replanting in the cleared areas to reduce the visual impact as much as possible.

A total of about 543 acres (220ha) of larch will be felled in Arran in an effort to control the disease.

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The removal of the trees is being carried out under a licence and once felled the timber can still be processed for uses such as wood chips.

Andy Walker, of FLS, said: "This is a horrible disease that can't be eradicated and has no known cure. The only way we have to slow its rate of spread is to fell the affected larch trees.

"It will result in substantial changes to some well-loved landscapes over the next few years but if we don't do this, then the long-term impact will be even worse."

He said residents and visitors to Arran could help prevent the spread of spores by cleaning mud from boots, bike wheels and dogs' paws before and after visits to woodland. FLS has more advice on its website.

Regulatory agency Scottish Forestry has been working with FLS on how to tackle the disease.

The organisation's Sasha Laing added: "The location and scale of infections on Arran have required us to develop our local regulatory approach to look to achieve the best disease control outcomes over the coming years.

"The approach taken allows due consideration of the unique landscape of Arran and the capacity of the forestry sector to deliver these outcomes."