A recent paper in the Scottish Forestry Journal (Scottish Forestry Volume 71, No.1 Spring/Summer 2017) looked at the impact of forestry operations on globally important freshwater pearl mussel populations and mitigation measures to conserve mussels. Many forestry plantations were created on peat soils requiring extensive drainage systems that then feed into natural watercourses. These drains release significant amounts of sediment and nutrients into natural watercourses to the detriment of freshwater pearl mussel populations as well as other aquatic animals. When trees are felled, either as part of rotational forestry or for forest-to-bog restoration, large amounts of sediment can be released into natural watercourses. In one forest block in the north of Scotland mitigation measures in the form of plastic piling dams were installed into forestry drains prior to harvesting. This simple and low cost action prevented the release of sediments into watercourses containing freshwater pearl mussels.
This management practice of blocking forestry drains prior to harvesting is relevant to all forest-to-bog restoration projects as it will have major benefits to water quality and aquatic biodiversity downstream of the harvesting site. Forest Enterprise Scotland is now rolling out this simple management practice to all its sites across Scotland, irrespective of the presence of freshwater pearl mussels. Similarly, Peatland Action will be expecting all forest-to-bog restoration projects to follow this standard practice due to the benefits to freshwater ecosystems. This type of pre-harvest action could be adopted across the UK as part of best practice forest management.
