Editor’s summary

Rings provide a wealth of information on how trees have responded to past environmental change. However, a relative lack of tree-ring data from the tropics limits inferences on these globally important ecosystems. Zuidema et al. compiled tree-ring data from 150 species in sites spanning the tropics and subtropics to determine how tropical trees have responded to drought since 1930. Overall, drought had surprisingly small effects on tree growth, and these deficits were mostly offset by higher growth in the wettest years. Gymnosperms experienced larger growth deficits, especially during the dry season, whereas wet-season droughts were more detrimental for angiosperms. Increasing drought frequency and severity may lead to stronger growth deficits. —Bianca Lopez

Abstract

Increasing drought pressure under anthropogenic climate change may jeopardize the potential of tropical forests to capture carbon in woody biomass and act as a long-term carbon dioxide sink. To evaluate this risk, we assessed drought impacts in 483 tree-ring chronologies from across the tropics and found an overall modest stem growth decline (2.5% with a 95% confidence interval of 2.2 to 2.7%) during the 10% driest years since 1930. Stem growth declines exceeded 10% in 25% of cases and were larger at hotter and drier sites and for gymnosperms compared with angiosperms. Growth declines generally did not outlast drought years and were partially mitigated by growth stimulation in wet years. Thus, pantropical forest carbon sequestration through stem growth has hitherto shown drought resilience that may, however, diminish under future climate change.

Pieter A. Zuidema et al. "Pantropical tree rings show small effects of drought on stem growth" Science 389,532-538 (2025). DOI:10.1126/science.adq6607

Contact

Prof. Dr. Frank Riedel
paleobio@zedat.fu-berlin.de

Dr. Gerhard Helle
ghelle@gfz.de