IT plays a crucial role in sustaining some of our most iconic species, from the white-tailed eagle to the Atlantic salmon.
Now the public body responsible for Scotland’s natural heritage has launched a £50,000 bid to assess how much “riparian woodland” remains north of the border, how much the country needs to meet net-zero targets – and how much expanding it would cost.
Riparian woodlands are the trees and shrubs that grow along the banks of burns, rivers and lochs.
Dominated by willow and alder, they provide a vital habitat for a variety of animals, while their shade helps lower water temperatures.
NatureScot, formerly Scottish Natural Heritage, said the increasing impact of climate change “makes riparian woodlands much more important”.
But it warned Scotland has lost most of its natural riparian woodland over a long period, “principally by high grazing impacts in the uplands, and perhaps through farm management in the lowlands”.
It is now seeking to commission a study into the issue, with a document posted to the Public Contracts Scotland website warning we are in the midst of a wider “biodiversity crisis”.
It added: “The absence of riparian woodlands has a negative impact on freshwater biodiversity and river channel morphology even under stable circumstances, but climate change is rapidly making the absence of riparian woodland cover an acute problem.”
NatureScot said it wants “to establish the existing riparian woodland resource in Scotland, to assess our future need, and to identify approaches to expanding riparian woodlands, and the costs associated with these”.
The estimated value of the research contract is £48,000.
In a document, NatureScot said Scotland’s freshwater systems are “exposed to increasing water temperatures due to lack of shading and channels becoming wider and shallower”.
Meanwhile, the absence of “woody material” has had an impact on the “mosaic of habitats that would be found in naturally functioning river systems”.
A spokeswoman told The Herald: “The increasing impact of climate change makes riparian woodlands much more important – for example the River Gairn in Aberdeenshire reached 27.5C in 2018 – close to the temperature where the river could not support salmon.”
She added: “Research suggests that we need riparian woodland along about half of the bank length, and so we’ve commissioned this research to find out how much we have got, and how far we are from that target.
“NatureScot did a small assessment of the River Dee upstream from Ballater in 2016 and concluded that we would need to restore about 220 miles to reach that target, so we expect that nationally we’ll see a substantial lack of riparian woodland.”
The spokeswoman said riverbanks and burnsides “are pretty good places for trees to grow” as long as grazing is controlled.
She added: “To date, riparian woodland restoration has focussed on planting in small exclosures to protect from grazing, particularly by deer in the uplands.
“These are great, but we need to move quickly beyond small-scale restoration to start growing the hundreds of miles of riparian woodlands we need.
“In this project we’re looking at the feasibility and cost of changes to deer management to allow riparian woodland to grow along whole river systems.
“This is a research project rather than practical woodland creation, but we hope the information will be useful to the many organisations aiming to expand these woodlands.”