Drought stress and tree size determine stem CO2 efflux in a tropical forest

• DOI: 10.1111/nph.15024
• Publication Date: 2018-02-03T18:16:46Z
• Authors: Lucy Rowland; Antonio C. L. da ...; Alex A. R. Oliveira; Rafael S. Oliveira; Paulo L. Bittencourt; Patricia B. Costa; Andre L. Giles; Azul I. Sosa; Ingrid Coughlin; John L. Godlee; Steel S. Vasconcelos; João A. S. Junior; Leandro V. Ferreira; Maurizio Mencuccini; Patrick Meir
• Keywords: Tropical forest; Tropical climate; Carbon sink

Summary CO 2 efflux from stems ( 2_stem ) accounts for a substantial fraction of tropical forest gross primary productivity, but the climate sensitivity this flux remains poorly understood. We present study 215 trees across wet and dry seasons, at world's longest running drought experiment site. show 27% increase in season droughted relative to control forest. This was driven by increasing 10–40 cm diameter. Furthermore, we that increases proportion maintenance growth respiration > 20 diameter, including large largest trees, 40 However, found no clear taxonomic influence on were unable accurately predict how altered ecosystem scale , due uncertainty introduced contrasting methods previously employed fluxes. Our findings indicate under future scenarios elevated drought, may augment carbon losses, weakening or potentially reversing sink. uncertainties scaling fluxes, stand‐scale estimates changes stem emissions remain highly uncertain.