Conversion from coniferous to broadleaved trees can make European forests more climate-effective

The climate effectiveness of forestation in Europe has been debated, as it may provide more warming via solar energy absorption than evaporative cooling. Given that forests play an important role in European climate policy, it is necessary to explore potential solutions to this issue in a warmer world. Based on experiments conducted with a regional climate model under several forest change scenarios, we find that conversion from coniferous to broadleaved trees in present-day forests can provide cooling for summer hot extremes (e.g.,, the monthly mean daily maximum temperature in July over Continental Europe is reduced by 0.6°C through the conversion). The conversion can also mitigate the undesired warming impacts of forestation with present-day forest composition in most of Europe, e.g., from +0.3°C to -0.7°C, also on the monthly mean daily maximum temperature in July over Continental Europe. This study highlights the importance of considering tree species in European forest policy development and also suggests that the Northern and Central regions should be prioritised for forestation over the Western and Southern parts.