Pantropical tree rings show small effects of drought on stem growth

[Data and materials availability:] All tree growth anomalies during and after drought years from the 483 tree-ring chronologies included in the study are provided as data S1. All 483 chronologies (from 1930 onward) are publicly available at Dryad (54). Raw tree-ring width measurements for all 483 chronologies are publicly available free of charge and for all research purposes on the International Tree-Ring Data Bank (ITRDB) (55). Links to the raw data of all 483 chronologies available on the ITRDB are included in data S1 and in the file metadata_FINAL.csv on Dryad (54). All code to build chronologies from raw tree-ring data, process climate data, conduct superposed epoch analyses, analyze statistics, and produce figures has been deposited on Dryad (54).

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.

This work was supported by AECID grant 11-CAP2-1730 (J.J.C.); Agencia Nacional de Promoción Científica y Tecnológica, Argentina grant PICT 2014-2797 (M.E.F.); Agencia Nacional de Promoción Científica y Tecnológica, Argentina grant PICT 2019-01336 (M.E.F.); BBVA Foundation (J.J.C.); Belspo BRAIN grant BR/143/A3/HERBAXYLAREDD (H.B.); CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (T.L.S.); CAPES grant 88887.199858/2018-00 (G.A.P.); CAPES grant 88887.495294/2020-00 (B.H.); CAPES (P.G.); CAPES/PDSE grant 15011/13-5 (M.A.P.); CGIAR (M.M.); CNPq grant 140849/2015-7 (A.K.M.); CNPq ENV grant FRG 0339638 (O.D.); CNPq grant 1009/4785031-2 (G.C.); CNPq grant 140277/2024-2 (D.B.C.C.); CNPq grant 311247/2021-0 (J.S.); CNPq grant 405923/2021-0 (M.C.S.); CNPq grant 406062/2023-4 (M.C.S.); CNPq grant 441811/2020-5 (J.S.); CNPq grant PQ 313129/2022-3 (A.C.B.); CONACYT Consejo Nacional de Ciencia y Tecnología México master fellowship (M.I.L.H.); CONACYT grant CB2016-283134 (J.V.D.); CONACYT grant CB-2016-283134 (L.R.C.E.); CONAFOR-CONACYT grant C01-234547 (J.C.P.); CONAFOR-CONACYT grant CONAFOR-2014 (L.R.C.E.); CONCYTEC Peru and World Bank grant 043-2019-FONDECYT-BM-INC.INV (J.G.I.); CONICET grant PIP-11220200102929CO (M.E.F.); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (E.A.F.); Copel Geração e Transmisão S.A. grant PD-06491-0405-2015 (A.K.M.); CUOMO Foundation (M.M.); DAAD (M.I.); DFG grant BR 1895/15-1 (A.B.); DFG grant BR 1895/23-1 (A.B.); DFG grant BR 1895/29-1 (A.B.); Dirección de Investigación de la Universidad Nacional de Loja (D.P.C.); Dirección General de Asuntos del Personal Académico of the UNAM (Mexico) (R.B.); Estudios dendrocronológicos en las Sierras Madre Occidental, Oriental y del Sur de México, grant 38111-4251030012346 (E.C.O.); FACEPE grant IBPG-1418-5.00/21 (D.B.C.C.); FAPEAM grant 01.02.016301.02630/2022-76 (J.S.); FAPEMAT (F.A.L.); FAPEMIG grant APQ-01544-22 (A.C.B.); FAPEMIG grant APQ-02541-14 (G.A.P.); FAPESC grant 2019TR65 (T.A.B.F.); FAPESP grant 12/50457-4 (G.C.); FAPESP grant 2009/53951-7 (M.T.F.); FAPESP grant 2017/50085-3 (G.C., G.M.L., and D.R.O.R.); FAPESP grant 2018/01847-0 (P.G.); FAPESP grant 2018/07632-6 (M.G.V.); FAPESP grant 2018/22914-8 (D.R.O.R.); FAPESP grant 2018/24514-7 (J.R.V.A.) FAPESP grant 2019/08783-0 (G.M.L.); FAPESP grant 2019/09813-0 (M.G.V.); FAPESP grant 2020/04608-7 (D.R.O.R.); FAPESP-NERC grant 18/50080-4 (G.C.); FAPITEC (C.S.L. and A.S.R.); FAPITEC/SE/FUNTEC grant 01/2011 (M.A.P.); FCT - Portuguese Foundation for Science and Technology grant UIDB/04033/2020 (J.L.P.C.L.); FONDECYT grant BM-INC.INV 039-2019 (M.E.F.); Fulbright Fellowship (B.J.E.); German Academic Exchange Service (DAAD) (M.R.); German Research Council (M.M.); HELVETAS Swiss Intercooperation (M.E.F.); IAI-SGP-CRA grant 2047 (J.V.D.); IFS grant D/5466-1 (J.H.S.); IFS grant D/5466-1 (J.N.); Inter-American Institute for Global Change Research IAI (F.A.R.); ITTO Fellowship Award 046/12S (E.J.R.R.); Lamont Climate Center (B.M.B.); Mahidol University grant FRB660042/0185 (N.P.); María Zambrano postdoctoral research program MZ2021 (RaAS); Minciencias grant 1118-714-51372 (I.R.N.M.); Ministerio Ciencia grant TED2021-129770B-C22 (R.S.S.); National Geographic Global Exploration Fund grant GEFNE80-13 (I.R.); National Natural Science Foundation of China grant 31870591 (P.F.); National Research Council of Thailand (NRCT) grant N42A660392 (P.T.); NSF grant AGS-1501321 (D.G.S.); NSF (B.M.B.); NSF CREST grant 0833211 (K.S.F.); NSF grant IBN-9801287 (A.J.L.); NSF grant AGS-1501321 (G.A.P.); NSF grant AGS-2102888 (J.M.); NSF grant AGS-2102938 (G.L.H.); NSF grant GER 9553623 (B.J.E.); NSF postdoctoral fellowship (B.J.E.); NSF-FAPESP PIRE grant 2017/50085-3 (C.F. and M.T.F.); NSF-FAPESP PIRE grant 2019/27110-7 (C.F.); NUFFIC (J.H.S. and J.N.); NUFFIC-NICHE (E.M.); PIRE-CREATE grant 2017/50085-3 (M.G.V.); PROCAD-AM grant 88887.625854/2021-00 (B.H.); Proyectos de generacion de conocimiento grant PID2021-123675OB-C44 (R.S.S.); Schlumberger Foundation (J.H.S. and J.N.); short-term fellowship from the Smithsonian Tropical Research Institute (RaAS); Sigma Xi (A.J.L.); Spanish Agency for International Development Cooperation (K.P.V.); Thailand Science Research and Innovation Fund Chulalongkorn University (P.T.); The Copperbelt University (J.H.S. and J.N.); The National Institute of Science and Technology in Plant Physiology under Stress Conditions grant 406455/2022-8 (F.A.L.); UK NERC grant NE/K01353X/1 (E.G.); UKRI grant EP/X025098/1 (N.J.L.); UKRI grant NE/B501504 (N.J.L.); UNAM-PAPIIT grant IN110223 (L.V.S.); Universidad Autónoma Agraria Antonio Narro (E.C.O.); World Wildlife Fund (WWF) (K.P.V.); Xunta de Galicia grant ED431C 2023/19 (G.P.L.); and Xunta de Galicia grant ED481D 2023/012 (G.P.L.).

Peer reviewed