The UK experiences frequent storms and high winds, which are a major threat to our forests, especially in upland and western areas. The UK has experience of managing wind risk, however the risk of wind damage and windthrow is expected to increase with climate change, with more frequent storms, an increase in wind speed, an increase in winter rainfall, and faster tree growth.

The projected increase in winter rainfall is likely to increase wind risk, as rooting depth and root anchorage are both reduced in waterlogged soils. An increase in tree growth rate due to warmer temperatures is possible in areas where moisture availability is not limiting, this could increase wind risk with stands reaching a critical height earlier.

Windthrow risk is influenced by:

• The exposure of the site, with higher wind speeds occurring in western areas and at higher elevations
• Tree species and rooting form, with both shallow rooting and faster growing species more vulnerable
• Soil type, drainage, and rooting depth; with shallow, water-logged, or sandy soils at increased risk
• Stand spacing; open grown trees exposed to wind are at a lower risk, as are closely spaced (<2 m) stands
• Thinning regime; regular thinning of low-moderate risk stands can reduce risk, however stands are at highest risk after thinning. In high-risk areas, no-thin practices or self-thinning mixtures are suitable
• Tree height; the turning momentum increases with height, which restricts rotation length

Wind risk constrains forest management by restricting rotation length, thinning regime, and species selection in high-risk areas. Wind exposure affects tree growth, stem form and timber quality.

Storm damage can increase harvesting costs, reduce timber value, affect amenity value, damage wildlife habitats, restrict public access, close trails, and create safety concerns for forest workers and visitors. Forest facility closures can affect the local economy, by reducing tourism and recreation revenues.