How to strengthen the European forest carbon sink through prestoration: integrating active restoration and adaptation

Climate change-induced stress and disturbances threaten European forests’ biodiversity and ecosystem services. Today, climate change is advancing much faster than tree species can adapt to new conditions or migrate to regions with a suitable climate. Geographic barriers and land-use driven habitat fragmentation slow down natural dispersal and adaptation processes or make them ineffective, and thus further limit passive restoration (restoration with no or limited human interference). According to latest scientific evidence, the annual forest carbon sink of Europe is projected to decline by about 30–40% by 2061–2080, depending on the climate change scenario, if forest restoration only uses local tree populations, as some of them become climatically maladapted. Active forest restoration combined with assisted migration (prestoration), i.e. using always the climatically most suitable European tree species and populations, has the long-term potential to enhance carbon sequestration significantly compared to restoration efforts without assisted migration.