Hydraulically‐vulnerable trees survive on deep‐water access during droughts in a tropical forest

Deep-water access is arguably the most effective, but under-studied, mechanism that plants employ to survive during drought. Vulnerability embolism and hydraulic safety margins can predict mortality risk at given levels of dehydration, deep-water may delay plant dehydration. Here, we tested role in enabling survival within a diverse tropical forest community Panama using novel data-model approach. We inversely estimated effective rooting depth (ERD, as average water extraction), for 29 canopy species by linking diameter growth dynamics (1990–2015) vapor pressure deficit, potentials whole-soil column, leaf vulnerability curves. validated ERD estimates against existing isotopic data potential water-access depths. Across species, deeper was associated with higher maximum stem conductivity, greater xylem embolism, narrower margins, lower rates extreme droughts over 35 years (1981–2015) among evergreen species. Species exposure stress declined indicating trees compensate stress-related through access. The mitigating hydraulically-vulnerable has important implications our predictive understanding under current future climates.