Tree Regeneration After Unprecedented Forest Disturbances in Central Europe Is Robust but Maladapted to Future...

Central Europe has been a hotspot of forest disturbance during 2018-2020, with large pulses of tree mortality from drought and bark beetles. Post-disturbance recovery is crucial for forest resilience and the continued provision of ecosystem services. We surveyed 849 plots in disturbance hotspots across 10 Central European countries to assess the state of early (3-5 years) post-disturbance tree regeneration. Our specific objectives were to quantify post-disturbance tree recovery, identify key drivers, and assess future trajectories using model-based analyses. We found robust tree recovery throughout Central Europe, with median stem densities of 4750 n ha^-1. Only 7% of plots had no regeneration. Regeneration density increased with precipitation, particularly at warm sites, and decreased with disturbance severity and size. The most frequently regenerating tree species was Picea abies (present on 48% of plots), a species that is poorly adapted to future heat and drought. Overall, we found that 75% of the currently established trees are projected to be outside of their climatic niche by the end of the century under moderate climate change (RCP4.5). We conclude that while Central European forests recover well from recent disturbances, they lack sufficient post-disturbance reorganization to enable sufficient adaptation to future climate.