Woodland plan to stop Rest and Be Thankful landslides

The area has been hit by landslides -  BEAR Scotland/PA
The area has been hit by landslides - BEAR Scotland/PA

IT HAS been plagued for years by landslides from the mountain above, and was this year closed for weeks on end, giving people living in west Argyll a major headache.

Despite £13 million spent on concrete and steel barriers to stop slips on the A83 Rest and Be Thankful, Beinn Luibhean keeps on falling onto the road. The Scottish Government has even mooted hugely expensive alternative routes such as a bridge across the Clyde.

But this month a scheme costing just half a million pounds begins to plant 250,000 trees on the mountain. Their roots can stop landslides before they start, preventing long delays and even 60-mile detours caused by some slides.

Around 400 acres above the road in upper Glen Croe will be covered in birch, oak, blackthorn, willow and other water-tolerant species. It is the first time in the UK such a large tract has been planted to stabilise a slope.

The effects of the trees binding the soil will be felt almost immediately, according to Government foresters, and the scheme could help ensure the existing road can continue to be used.

Intense rainfall events which trigger slides are likely to become more common with global warming, and it is hoped the scheme can show how to stop landslides elsewhere.

When the main road is shut, traffic is usually convoyed along the lower single-track old road which has been upgraded, but even this was closed for days this year by slides.

A landslide at the Rest and be Thankful on the A83, west of Loch Lomond - Strathclyde Police/PA
A landslide at the Rest and be Thankful on the A83, west of Loch Lomond - Strathclyde Police/PA

With growing anger in Argyll over closures and delays, the Scottish Government is consulting on a number of alternative routes. These include bridging the Firth of Clyde and Loch Fyne, or running a connecting road from the A82 to the north, itself notorious as one of the UK’s worst roads.

Continued use of the existing road line is most likely, and the tree scheme could make it possible.

Fencing teams will move in later this month to start to work to keep out tree-munching sheep and deer. Trees and fencing will be helicoptered in for planting next year by hand, as machinery could itself trigger slides on the sensitive slope.

Forestry and Land Scotland (FLS) – formerly Forestry Commission Scotland – is carrying out the Government-funded scheme.

Government forestry researcher Bruce Nichol came up with the plan, and said: “You only have to walk into a woodland in a rainstorm to notice how much protection you get from trees – they’re like an umbrella.

“As well as the branches and leaves slowing the water down the roots are absorbing water so they’re reducing the water content. Possibly most importantly the roots bind the soil together, so they have a very big impact on its strength.”

Bear Scotland has maintained the road for seven years on behalf of Transport Scotland, with an average of one landslide blockage a year, and is building the conventional defences.

Eddie Ross, the company’s north-west representative, said: “I’d like to see the trees as another weapon in our armoury. I don’t think it will necessarily save every landslide but it must make quite a significant difference.”

John Hair of FLS said: “The lessons we learn here can be applied to numerous other sites including rail sites, trunk roads, above communities and other pieces of infrastructure.”

Heavy rain is thought to have caused the landslide that hit a train near Stonehaven in August, killing three people.