Low growth resilience to drought is related to future mortality risk in trees

Severe droughts have the potential to reduce forest productivity and trigger tree mortality. Most trees face several drought events during their life and therefore resilience to dry conditions may be crucial to long-term survival. We assessed how growth resilience to severe droughts, including its components resistance and recovery, is related to the ability to survive future droughts by using a tree-ring database of surviving and now-dead trees from 118 sites (22 species, >3,500 trees). We found that, across the variety of regions and species sampled, trees that died during water shortages were less resilient to previous non-lethal droughts, relative to coexisting surviving trees of the same species. In angiosperms, drought-related mortality risk is associated with lower resistance (low capacity to reduce impact of the initial drought), while it is related to reduced recovery (low capacity to attain pre-drought growth rates) in gymnosperms. The different resilience strategies in these two taxonomic groups open new avenues to improve our understanding and prediction of drought-induced mortality.

Lucía DeSoto, Maxime Cailleret, Frank Sterck, Steven Jansen, Koen Kramer, Elisabeth M.R. Robert, Tuomas Aakala, Mariano M. Amoroso, Christof Bigler, J. Julio Camarero, Katarina Čufar, Guillermo Gea-Izquierdo, Sten Gillner, Laurel J. Haavik, Ana-Maria Hereş, Jeffrey M. Kane, Vyacheslav I. Kharuk, Thomas Kitzberger, Tamir Klein, Tom Levanič, Juan C. Linares, Harri Mäkinen, Walter Oberhuber, Andreas Papadopoulos, Brigitte Rohner, Gabriel Sangüesa-Barreda, Dejan B. Stojanovic, Maria Laura Suárez, Ricardo Villalba, Jordi Martínez-Vilalta