Hydraulic adaptability promotes tree life spans under climate dryness

Abstract

AbstractAimTree life spans, as an important determinant of carbon turnover in forest ecosystems, are strongly linked to climate change. Enhanced drought has led to extensive tree mortality, but whether climate dryness will widely shorten tree life spans remains unclear. Here we aimed to establish the relationship between climate dryness and tree life span, and identify the regulatory effects of functional traits on tree life span.LocationGlobal.Time periodUntil 2015.Major taxa studiedWoody plants.MethodsWe used tree ring records sampled at 2,348 sites ranging from the tropics to Arctic regions to estimate tree life span. First, we investigated which of nine functional traits related to trees' adaptability best explained the variation in tree life span. Second, we established a structural equation model between climate dryness, functional traits and tree life span to illustrate the regulatory effects of climate dryness and trees' adaptability on tree life span.ResultsOur results suggested that tree life span significantly increased with climate dryness across biomes. Hydraulic traits indicating the adaptability of trees to climate dryness regulated the relationship between climate dryness and tree life span. Trees with high‐density wood or with high resistance to drought‐induced embolisms extend their life span with increasing climate dryness, but climate dryness reduces the life spans of low‐drought‐tolerance trees.Main conclusionsTree life span is not fixed within species but regulated by climate dryness and trees' hydraulic adaptability to drought. Our large‐scale links between climate change and tree life span allow for incorporation of these factors into future Earth system models for a better representation of climate‐driven forest dynamics.