Nature Communications

Long-term decline in above-ground carbon sinks in Brazilian tropical and subtropical forests

2026-08-17

Recent evidence indicates that Brazilian forests are shifting from persistent carbon sinks to emerging carbon sources, with important implications for the global climate. To investigate this trend, we analyse long-term census data from 49 forest sites spanning southeast and southern Brazil, including tropical and subtropical forests. We examine above-ground carbon dynamics and its relationship with tree diversity and functional traits that are tightly linked with species’ carbon processing and storage capacities. Our findings reveal a long-term trend of taxonomic, functional and phylogenetic homogenisation and a decline in the forests’ above-ground carbon sink. Specifically, homogeneous forests have lower carbon losses, whilst forests with more conservative species are associated with greater carbon gains and lower carbon losses. Overall, our study establishes a baseline to understand and predict the above-ground carbon sink in the face of ongoing climate change in this region.

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DOI https://doi.org/10.1038/s41467-026-74921-0