Sustainable Scotland: Storm-damaged trees sunk in River Dee to boost nature and help save wild salmon

Around 50 trees which survived last year’s devastating Storm Arwen have been relocated and dug into the banks and bed of one of Scotland’s most famous salmon rivers to boost the survival chances of the ‘king of fish’.

The pioneering work is part of wider conservation efforts being carried out on the Dee. Beltie burn, in the upper reaches of the river catchment, has already been ‘renaturalised’ by reinstating natural bends and meanders, planting new native trees, restoring dried out wetlands and reconnecting salmon breeding grounds.

Now, as part of a second major phase of work aimed at restoring biodiversity and boosting resilience to climate change at the award-winning site, 50 mature trees from Scolty Forest in Aberdeenshire which were damaged by the powerful storm last November have been embedded along the watercourse.

The trees, complete with their root plates, were customised into 15 large woody structures which have been dug in to the banks and riverbed to create habitats for wildlife and further slow the flow of water during periods of heavy rain and flooding.

The ambitious £12,000 project, spearheaded by the Dee Catchment Partnership, is a collaboration between the Dee District Salmon Fishery Board, Cairngorms National Park Authority and Forestry and Land Scotland.

Edwin Third, river operations manager for the Dee District Salmon Fishery Board, led the design and installation of the large woody structures into the Beltie. He has coordinated the addition of nearly 150 such structures to watercourses throughout the upper catchment in recent years.

“These rivers once flowed through a wooded landscape,” he said. “Riverside trees would have been a vital part of the habitat structure, providing shade, shelter and food, as well as pools and gravel beds when they fall into the river, where aquatic species can hide from predators. Nowadays these must be among the rarest habitats in Scotland, and with Atlantic salmon in crisis we urgently need to get them back.

“Salmon have a very complex life cycle, requiring different types of habitat at different stages. By adding large woody structures to the river we can help to create these complex and diverse habitats for them. But we also support all the native wildlife – interrupting and trapping vegetation and boosting aquatic insects, creating feeding platforms for birds like dippers and the kind of entangled, protective structures that otters love.

Around 50 trees which were damaged when the powerful Storm Arwen ripped through Scolty Forest in Aberdeenshire last year have been secured into the Beltie burn in Deeside as part of a second major phase of restoration work aimed at boosting biodiversity and climate resilience at the site

“The benefits are widespread. Salmon will be navigating these structures in the next few weeks as they make their way up the Beltie to spawn.”

Dr Susan Cooksley, a freshwater ecologist at the James Hutton Institute and manager for the Dee Catchment Partnership, said: “This is an exciting next phase in the recovery of the Beltie burn, which we restored two years ago from an artificially straightened channel to a vibrant wetland system flowing into a meandering stream, to boost biodiversity and the region’s resilience to flooding. Since then the site has had time to heal and develop naturally.”

She said adding the storm-damaged trees was a no-brainer due to their ready availability. “It was the obvious next step for the Beltie – to create a variety and complexity of habitats for nature, just as beavers do, and improve the connectivity between the river and its floodplain by raising the level of water,” she said.

“It has also given us a chance to hone our skills in creating these structures in more silty, low-lying streams. We have learnt a lot from these works at the Beltie and this will allow us to tackle other projects in the area with confidence.”

The storm-damaged trees will provide food, shelter and shade for wild salmon in the River Dee catchment, and hopefully help stop population declines in the 'king of fish'

Philippa Murphy, environment advisor for Forestry and Land Scotland, which donated the trees and funded their transportation to the site, added: “It’s fantastic to see these trees being repurposed for nature in this way, and we were delighted to be involved in the project.”

Beltie burn, near Torphin in Aberdeenshire, was first artificially straightened in the mid-18th century for agricultural improvements and then again later to make way for the Deeside Railway line.

The restored site, which is backed by NatureScot’s Biodiversity Challenge Fund, has been closely monitored since works began in 2020 to help build an accurate picture of the impacts of the measures. As one of the first partnerships in the country to add large woody structures to watercourses, the team will continue to document progress to help develop similar techniques in river projects elsewhere in Scotland.

Fisheries on the Dee have planted 250,000 saplings along its key tributaries. They plan to plant a million in the Dee's catchment by 2035, including native rowan, aspen, Scots pine, birch, willow, hawthorn and juniper, all aimed at creating the light and shade blend preferred by salmon.