Specific leaf area and vapour pressure deficit control live fuel moisture content

作者：Anne Griebel, Matthias M. Boer, Chris J. Blackman, Brendan Choat, David S. Ellsworth, Paul A. Madden, Belinda E. Medlyn, Víctor Resco de Dios, Agnieszka Wujeska‐Klause, Marta Yebra, Nicolas Younes Cardenas, Rachael H. Nolan · 发表于：Functional Ecology · 年份：2023 · DOI：10.1111/1365-2435.14271 · 被引用次数：46 · 研究领域：Plant Water Relations and Carbon Dynamics、Fire effects on ecosystems、Plant responses to elevated CO2

Abstract The live fuel moisture content (LFMC) is an important precondition for wildfire activity, yet it remains challenging to predict LFMC due to the dynamic interplay between atmospheric and hydrological conditions that determine the plant's access to, and loss of water. We monitored LFMC and a range of plant water‐use traits (predawn and midday leaf water potentials [Ψ leaf ]), leaf traits (specific leaf area [SLA]), hydrological status (soil water content [SWC] in the shallow layer and full profile) and atmospheric variables (air temperature, vapour pressure deficit [VPD], CO 2 concentrations) in a mature eucalypt woodland at the Eucalyptus Free‐Air CO 2 Enrichment (EucFACE) facility during a drought. We combined plant traits, hydrological status and atmospheric variables into a biophysical model to predict LFMC dynamics, and compared these with predictions of LFMC based on a satellite model and established relationships between Ψ leaf and LFMC from pressure–volume curves. Predawn Ψ leaf could be well predicted from changes in SWC, but variation in midday Ψ leaf and LFMC were more responsive to atmospheric than hydrological variables. The biophysical model explained up to 89% of variability in LFMC and outperformed established approaches to predict LFMC. SLA was the single most important variable to predict LFMC, followed by VPD, which explained 33% of the remaining variability in LFMC. Our study demonstrates that the co‐variation of plant traits and atmospheric and hyd...