SENCE Case Study – Informing Afforestation Policy

Black Grouse
Black grouse a threatened species with important but fragmented populations in north Wales
To help mitigate the impacts of climate change and achieve benefits in other areas such as reduced flood risk, the Welsh Government (WG) has committed to an ambitious target to significantly increase woodland expansion by 2000 ha per year. To optimise the outputs of afforestation across Wales, and to demonstrate how nature-based solutions can work in practice, a holistic understanding of the multiple benefits provided by different types of woodland is required. Putting the right tree in the right place at the right sort of planting density could have great benefits not just in terms of ecosystem services such as carbon capture, flood mitigation and water quality but also for key species that use different parts of the woodland ecosystem.

This is the subject of a project being carried out with the RSPB. Environment Systems has been commissioned to investigate a number of different scenarios to benefit both ecosystem services and species. In this project, the focus has been on black grouse (Tetrao tetrix), which is a threatened species with important but fragmented populations in areas of north Wales. A moorland fringe species, black grouse inhabit areas containing a mosaic of wetland, heath, grassland, and woodland edge habitat. The thinking is that expanding the wooded areas in key places would increase the resilience of existing populations by connecting areas of fragmented habitat and connecting disparate populations. Planting in these areas is also likely to lead to an increase in water quality and a reduction in water flow peaks which can help flood alleviation. There are therefore good reasons to consider tree planting in specific areas to achieve these multiple benefits.

In this WG funded project RSPB are carrying out research into the diversity of bird species associated with different woodland types, whilst Environment Systems are carrying out carbon storage and sequestration analyses, surface water regulation modelling, and tree-planting opportunity modelling. There is a rich source of up-to-date data available, which makes the modelling work more compelling. We are building on previous work on ‘GIS for Area Statements’ for Natural Resources Wales (NRW), and a series of datasets modelling biophysical suitability for tree planting, created for WG under the Capability, Suitability and Climate Programme. The analyses using our SENCE technology combine these datasets to identify areas where the soil, topography and climate are suitable for growing trees, but also considers real world constraints, excluding areas where it would not be possible or desirable to plant trees (areas of deep peat, Scheduled Ancient Monuments etc), and areas where tree planting may be possible but additional factors must be considered (‘sensitivities’ e.g., acid sensitive catchments, common land etc).

Tree planting opportunities
Tree planting opportunities maps, commercial and environmental, for the Dee catchment in north Wales
Combining and building on the data from the NRW and Welsh Government projects allows us to consider biophysical, political and sociological influences on decision-making, and modify the decision rules to meet the specific habitat requirements of a priority species. In addition to the work on black grouse, the project is modelling tree-planting opportunity space in three wider catchments (Towy Valley, Elan Valley and the Dee), where the relative carbon and water regulation benefits derived from different afforestation strategies (‘commercial’ vs ‘environmental’) will be analysed.

The output will be used to demonstrate how species and the biodiversity of an area can and should be considered alongside other ecosystem services and planting considerations to give a truly holistic approach.

View the project reports: