Forest disturbances drive up Europe’s surface temperatures — recovery depends on extent, severity and stand structure

Europe-wide analyses that link satellite measurements of land surface temperature with comprehensive disturbance data show a clear pattern: storms, insect calamities, fires and clearings noticeably warm forested areas. The strength of the effect and the time until temperatures return to prior levels depend primarily on the size and severity of the disturbance and on forest properties.

Why disturbed forests become warmer

When canopy layers are torn open or die back, more sunlight reaches the ground, shading is lost and vegetation transpiration declines. That raises surface temperatures, especially during the growing season. Across large regions, satellite data reveal a consistent picture: freshly disturbed areas are significantly warmer than intact forests.

Extent and severity determine the thermal signature

Small, scattered gaps tend to produce more localized warming. Large-scale damage, by contrast, creates pronounced heat islands that can persist for weeks to years. Severe disturbances with major canopy loss amplify the effect and delay cooling because regrowth processes are slowed and more radiation reaches the ground unhindered.

Stand characteristics control recovery

Stands with rapid natural regeneration or active reforestation regain leaf area quickly — and with it cooling by shading and transpiration. Tree species that rebuild canopy rapidly accelerate the return to previous temperature conditions. Open, slow-growing stands maintain warming for longer. In addition, age, stocking density and soil conditions influence water availability and thus evaporative cooling.

Seasonal and regional differences

The warming effect is strongest during the growing season, when the contrast between intact transpiration and open areas is maximal. In regions with regular snowfall, loss of canopy in winter can locally increase albedo and lead to short-term cooling. There is no uniform seasonal pattern: summer warming often dominates, while opposing effects can occur in winter.

Role of land use and management

Whether disturbed areas are quickly reforested or converted to other uses shapes the micro- and mesoscale climate. Intensive timber use, large-scale clearcutting or conversion to agriculture delays the restoration of the cooling vegetation cover. Close-to-nature reforestation and structural diversity — such as mixed forests instead of monocultures — promote cooling after disturbances.

Implications for climate adaptation and health

When forests' cooling capacity is reduced by disturbances, heat stress for ecosystems and nearby settlements increases. Forests deliver not only carbon storage but also effective shading and evaporative cooling — services that should be considered in planning and adaptation strategies.

Practical approaches

Prevention and rapid, ecologically informed responses pay off: resilient mixed stands, continuous tending, containment of bark beetle spread and site-appropriate, climate-suitable tree species selection reduce the risk of large, severe losses. After disturbances, replanting and structural diversity speed up the return of cooling functions. Spatial planning should avoid creating large, contiguous open areas.

Outlook

The combination of remote sensing and disturbance data makes it possible to quantify and protect forests' climate services — in particular their cooling effect. Given increasing extreme events, the thermal effects of forest disturbances should be integrated into climate impact assessments and adaptive forest strategies.