Peatlands are very important for Scotland since they may cover, dependent on the definition and data source, up to 30% of the total land area, mostly occurring in the north and the country´s west. The Flow Country is the UK’s most extensive peatland region with over 400,000 ha of peat and wetland, of which around 67,000 ha is afforested.
Afforestation of peatlands in Scotland started already in the 18th century but the extent and success was limited before the mid-20th century. Large areas of conifer forest were planted on Scottish peatland between 1940s to the 1980s with many of these plantations now reaching harvesting age.
With regards to UK´s total forest soil C stocks (up to 1 m depth thus excluding deep peat soils), estimates indicate that Scotland holds about 62% of the latter although it constitutes only 50% of the forest area. This is primarily due to Scottish large areas of forested organic soils. Research shows that carbon stored in Scotland’s soils (notably peat and peaty soil) is equivalent to over 180 years of greenhouse gas emissions from Scotland at current emission rates.
Scottish Government aims to restore 40% of the estimated 600,000 ha of damaged peatlands by 2030, which includes restoration of afforested peat bogs as well. A general presumption is to restock any felled woodlands; however, the Government’s Policy on the Control of Woodland Removal introduces allowances subsidies [MIP1] for not replanting on peatland sites that are a priority for restoration on ecological grounds, and on those peatlands that are not a priority for restoration when there would be a significant GHG benefit to restoring degraded peat. However, there is conflicting evidence on whether planting trees on peat leads to more carbon loss from peat than is gained by the trees.
Given this, the publication on the future of peatland forestry in Scotland considers three key options:
a) re-stocking plantations for a second rotation – likely in areas with good timber growth and economically viable timber harvest
b) restoration of plantations to open bog – mostly focused on removing trees and raising the water table (usually achieved by blocking ditches and furrows often with dams constructed of compressed peat or occasionally with plastic piling). It is expected that the complete forest-to-bog restoration will take decades making the restoration trajectories uncertain. However, it is believed that restoration is likely to yield benefits in the long-term, both with regards to carbon storage and biodiversity at the cost of timber´s economic value and the substantial cost of restoration itself. Peatland Action fund, which is run by Scottish Natural Heritage, in 2014 provided of £1.6 mil. for sequestering and storing carbon through the restoration of peatland. This action included 24 different sites across Scotland, all involving either blanket bogs or lowland raised bogs.
c) a ‘middle-way’ option which attempts to retain trees but without the negative consequences of commercial forestry.
Since each of these options faces practical issues and difficult trade-offs between the economic value of forestry, biodiversity and the value of peat as a carbon pool, the future of peatland forestry in Scotland is likely to be a mix of each of these possibilities with decisions on the most appropriate option to be done on site level. However, the latter is expected to be quite difficult due to large gaps in the underlying science.