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Amazonia contains the most extensive tropical forests on Earth, but Amazon carbon sinks of atmospheric CO₂ are declining, as deforestation and climate-change-associated droughts^{, , –} threaten to push these forests past a tipping point towards collapse^{, , –}. Forests exhibit complex drought responses, indicating both resilience (photosynthetic greening) and vulnerability (browning and tree mortality), that are difficult to explain by climate variation alone^{, , , , , , , –}. Here we combine remotely sensed photosynthetic indices with ground-measured tree demography to identify mechanisms underlying drought resilience/vulnerability in different intact forest ecotopes^, (defined by water-table depth, soil fertility and texture, and vegetation characteristics). In higher-fertility southern Amazonia, drought response was structured by water-table depth, with resilient greening in shallow-water-table forests (where greater water …