LAUSR

Abstract. Europe was affected by an extreme drought in 2018, compounding with an extensive heatwave in the same and subsequent years. Here we provide a first rapid assessment of the impacts this compounding event had on forest disturbance regimes in Europe. We find that the 2018 drought has caused unprecedented levels of forest disturbance across large parts of Europe, persisting up to two years post drought. The 2018 drought pushed forest disturbance regimes in Europe to the edge of their past range of variation, especially in Central and Eastern Europe. Increased levels of forest disturbance were statistically linked to low soil water availability in 2018, and were further modulated by high vapor pressure deficit from 2018 to 2020. We also document the emergence of novel spatiotemporal disturbance patterns following the 2018 drought (i.e., more and larger disturbances, occurring with higher spatiotemporal autocorrelation) that will have long-lasting impacts on forest structure, and raise concerns about a potential loss of forest resilience. We conclude that the 2018 drought had unprecedented impacts on forest disturbance regimes in Europe, highlighting the urgent need to adapt Europe's forests to a hotter and drier future with more disturbance.