Linkages between stem vulnerability curves and tree demography and their implications for plant physiological modeling.

This article investigates the relationships between vulnerability curve (VC) parameters—specifically maximum xylem hydraulic conductivity (Ks,max), xylem water potential at 50% loss of conductivity (P50), and the curvature parameter (a), which describes the steepness of the VC—and tree demographic rates (mortality, recruitment, and relative growth rate) in 16 canopy tree species from Panamanian seasonal tropical forests. The study finds that mortality and recruitment rates of evergreen species are significantly positively correlated with P50, while those of deciduous species correlate significantly with the curvature parameter a, highlighting its ecological importance, especially for deciduous trees. Additionally, evergreen species show a positive relationship between relative growth rate and Ks,max, a pattern not observed in deciduous species. These findings suggest that integrating measured VC parameters, including the often-overlooked curvature parameter a, into plant hydraulic models can improve predictions of forest dynamics and responses to water availability under climate change.