Adding large wood to rivers

Wood is part and parcel of a healthy river. Bankside trees and branches fall in during storms, creating dead wood that gives life to a river. The wood disrupts flow, creating pools and riffles, with knock on effects for the riverbed. In slow waters sediments settle in, and are swept out where the flow is swift, so that the riverbed becomes a complex mosaic of different habitats. These different habitats provide spawning sites, places to feed, and refuges from high flows and predators.

Dead wood was once a very common feature of our rivers but today it is rare to see large trees or branches in the water, simply because there is so little woodland in the uplands – this wood was seen as a danger, requiring to be removed. We now understand that the river system is impoverished as a result and so we’re adding wood in the form of whole trees.

64 large woody structures have been created in the last two years, mostly in the Gairn and Muick catchments, and lower down the catchment within the Easter Beltie Burn restoration. Dead trees are locally sourced and their placement carefully designed; the root ball needs to be well-anchored to hold the wood in place.

The wood placement will provide immediate benefits, but the long term solution is to build woodland cover back into our river system. We are doing this by planting 100s of km of bankside woodland and in decades to come, this will start to generate dead wood naturally. In the meantime our wood placements will kickstart the recovery process. These habitat improvements are well-supported by land managers who are keen to see immediate improvements for fish habitat and be involved in climate resilience projects. To evaluate the benefits of the project, sites are being monitored by PhD students from JHI/UoA (water temperatures), RDT (fish populations) and cbec (hydromorphology).

Lead Partners	Dee District Salmon Fishery Board River Dee Trust
Project Type	Creating habitats for wildlife Dee Catchment Management Plan Habitats RIver Engineering Species Water Quality Water Resources Research and monitoring Evaluating our restoration projects Student projects Restoring river beds and banks Supporting a green recovery Tackling the climate crisis Working for nature
Project Status	Current
Partner Organisations	Dee District Salmon Fishery Board River Dee Trust Glenmuick Estate Gairn Estates
Funders	SNH Biodiversity Challenge Fund

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