Climate-change-driven growth decline of European beech forests

The growth of past, present, and future forests was, is and will be affected by climate variability. This multifaceted relationship has been assessed in several regional studies, but spatially resolved, large-scale analyses are largely missing so far. Here we estimate recent changes in growth of 5800 beech trees (Fagus sylvatica L.) from 324 sites, representing the full geographic and climatic range of species. Future growth trends were predicted considering state-of-the-art climate scenarios. The validated models indicate growth declines across large region of the distribution in recent decades, and project severe future growth declines ranging from −20% to more than −50% by 2090, depending on the region and climate change scenario (i.e. CMIP6 SSP1-2.6 and SSP5-8.5). Forecasted forest productivity losses are most striking towards the southern distribution limit of Fagus sylvatica, in regions where persisting atmospheric high-pressure systems are expected to increase drought severity. The projected 21st century growth changes across Europe indicate serious ecological and economic consequences that require immediate forest adaptation.EMdC was supported and financed by the Alexander von Humboldt Foundation. CSZ and AB acknowledge funding by the Bavarian Ministry of Science and Arts from the Bavarian Climate Research Network (BayKliF); J.E. by the ERC advance project Monostar (AdG 882727) and SustES project (CZ.02.1.01/0.0/0.0/16_019/0000797); C.H. by the German Research Foundation (HA 8048/1-1); I.D.L. by Fundació La Caixa through the Junior Leader Program (LCF/BQ/LR18/11640004); S.M. by European Regional Development Fund (KK.05.1.1.02); K.C., M.M., J.G., and P.P. by Slovenian Research Agency ARRS, programs P4-0015 and P4–0107 and project J4-2541; B.S. by the Ministry of Education and Science of the Republic of Serbia (Project 451-02-68/2020/14/2000169); I.C.P. was supported by Romanian Ministry of Education and Research grant CNCS-UEFISCDI, project number PN-III-P4-ID-PCE-2020-2696, within PNCDI III. We thank the World Climate Research Programme and Earth System Grid Federation for hosting and promoting CMIP6, and Wolfram Elling and Christoph Dittmar for beech tree-ring data