Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests

Julia Valentim Tavares*, Rafael S. Oliveira, Maurizio Mencuccini, Caroline Signori-Müller, Luciano Pereira, Francisco Carvalho Diniz, Martin Gilpin, Manuel J. Marca Zevallos, Carlos A. Salas Yupayccana, Martin Acosta, Flor M. Pérez Mullisaca, Fernanda de V. Barros, Paulo Bittencourt, Halina Jancoski, Marina Corrêa Scalon, Beatriz S. Marimon, Imma Oliveras Menor, Ben Hur Marimon, Max Fancourt, Alexander Chambers-OstlerAdriane Esquivel-Muelbert, Lucy Rowland, Patrick Meir, Antonio Carlos Lola da Costa, Alex Nina, Jesus M. B. Sanchez, Jose S. Tintaya, Rudi S. C. Chino, Jean Baca, Leticia Fernandes, Edwin R. M. Cumapa, João Antônio R. Santos, Renata Teixeira, Ligia Tello, Maira T. M. Ugarteche, Gina A. Cuellar, Franklin Martinez, Alejandro Araujo-Murakami, Everton Almeida, Wesley Jonatar Alves da Cruz, Jhon del Aguila Pasquel, Luís Aragāo, Timothy R. Baker, Plinio Barbosa de Camargo, Roel Brienen, Wendeson Castro, Sabina Cerruto Ribeiro, Fernanda Coelho de Souza, Eric G. Cosio, Nallaret Davila Cardozo, Richarlly da Costa Silva, Mathias Disney, Javier Silva Espejo, Ted R. Feldpausch, Leandro Ferreira, Leandro Giacomin, Niro Higuchi, Marina Hirota, Euridice Honorio, Walter Huaraca Huasco, Simon Lewis, Gerardo Flores Llampazo, Yadvinder Malhi, Abel Monteagudo Mendoza, Paulo Morandi, Victor Chama Moscoso, Robert Muscarella, Deliane Penha, Mayda Cecília Rocha, Gleicy Rodrigues, Ademir R. Ruschel, Norma Salinas, Monique Schlickmann, Marcos Silveira, Joey Talbot, Rodolfo Vásquez, Laura Vedovato, Simone Aparecida Vieira, Oliver L. Phillips, Emanuel Gloor, David R. Galbraith

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


Tropical forests face increasing climate risk1,2, yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, Ψ50) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk3-5, little is known about how these vary across Earth's largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters Ψ50 and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both Ψ50 and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM50 forests. We propose that this may be associated with a growth-mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon6,7, with strong implications for the Amazon carbon sink.

Original languageEnglish
Pages (from-to)111-117
Number of pages7
Issue number7959
Early online date26 Apr 2023
Publication statusPublished - 4 May 2023


  • Biomass
  • Carbon/metabolism
  • Droughts
  • Forests
  • Trees/growth & development
  • Tropical Climate
  • Xylem/metabolism
  • Rain
  • Climate Change
  • Carbon Sequestration
  • Stress, Physiological
  • Dehydration


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