Canopy damage during a natural drought depends on species identity, physiology and stand composition

Abstract

Summary Vulnerability to xylem cavitation is a strong predictor of drought‐induced damage in forest communities. However, biotic features of the community itself can influence water availability at the individual tree‐level, thereby modifying patterns of drought damage. Using an experimental forest in Tasmania, Australia, we determined the vulnerability to cavitation (leaf P50) of four tree species and assessed the drought‐induced canopy damage of 2944 6‐yr‐old trees after an extreme natural drought episode. We examined how individual damage was related to their size and the density and species identity of neighbouring trees. The two co‐occurring dominant tree species, Eucalyptus delegatensis and Eucalyptus regnans, were the most vulnerable to drought‐induced xylem cavitation and both species suffered significantly greater damage than neighbouring, subdominant species Pomaderris apetala and Acacia dealbata. While the two eucalypts had similar leaf P50 values, E. delegatensis suffered significantly greater damage, which was strongly related to the density of neighbouring P. apetala. Damage in E. regnans was less impacted by neighbouring plants and smaller trees of both eucalypts sustained significantly more damage than larger trees. Our findings demonstrate that natural drought damage is influenced by individual plant physiology as well as the composition, physiology and density of the surrounding stand.

Leaf Economic and Hydraulic Traits Signal Disparate Climate Adaptation Patterns in Two Co-Occurring Woodland Eucalypts

“…Biotic habitat factors such as differences in the associated enemy and plant community may also alter the effects of climate-driven selection on a focal species [ 93 , 94 ]. In Tasmanian eucalypts, for example, the potential for co-occurring rainforest species to affect clines in foliar glaucousness was noted early [ 50 ], and a recent study showed that drought damage in two focal eucalypt species is differentially influenced by neighbouring tree species [ 95 ].…”

Linking leaf economic and hydraulic traits with early-age growth performance and survival of Eucalyptus pauciflora

“…wind, and water stress) ( Gora and Esquivel-Muelbert, 2021 ). For example, greater drought damage in faster growing individuals has been reported in tree species ( Martínez-Vilalta et al., 2012 ; Zang et al., 2014 ), including eucalypts ( Ammitzboll et al., 2020 ) (but see Britton et al., 2022 ), and may be due to physiological trade-offs or greater depletion of soil water reserves ( White et al., 2009 ; Wright et al., 2010 ; Gleason et al., 2016 ; Brodribb et al., 2020 ). In the present case, despite the above-average maximum temperatures experienced during the growing period ( Costa e Silva et al., 2019 ), the field trial studied was not subject to a major experiment-wide abiotic stress event, and mortality gradually accumulated consistent with biotic causes, including inter-tree competition.…”

“…In the present case, despite the above-average maximum temperatures experienced during the growing period ( Costa e Silva et al., 2019 ), the field trial studied was not subject to a major experiment-wide abiotic stress event, and mortality gradually accumulated consistent with biotic causes, including inter-tree competition. However, empirical studies indicate that the various biotic and abiotic causes of mortality may not be independent ( Camarero et al., 2016 ; Gleason et al., 2017 ; Britton et al., 2022 ). Thus, the changing patterns of size-dependent mortality with age may be complex and even species-specific ( Bigler and Veblen, 2009 ; Wright et al., 2010 ; Britton et al., 2022 ).…”

“…However, empirical studies indicate that the various biotic and abiotic causes of mortality may not be independent ( Camarero et al., 2016 ; Gleason et al., 2017 ; Britton et al., 2022 ). Thus, the changing patterns of size-dependent mortality with age may be complex and even species-specific ( Bigler and Veblen, 2009 ; Wright et al., 2010 ; Britton et al., 2022 ). These patterns are clearly worthy of further evaluation over time in trials such as ours, especially after extreme events or as changes in climate accrue…”

Influence of Juvenile Growth on Xylem Safety and Efficiency in Three Temperate Tree Species

“…However, prolonged drought conditions might ultimately lead to hydraulic failure because of continuous residual water loss via the cuticle and bark [7]. Under severe and prolonged water stress, xylem tensions therefore ultimately reach critical thresholds causing water-filled vessels to embolize, which disrupts the continuous water column and ultimately causes plant death [8][9][10]. Thus, the likelihood of hydraulic failure and xylem characteristics are supposed to be highly interconnected.…”