Site-level soil moisture controls water-use efficiency improvement and climate response in sugar maple: a dual dendroisotopic study

作者：Rachel Dietrich, Frederick W. Bell, Madhur Anand · 发表于：Canadian Journal of Forest Research · 年份：2021 · DOI：10.1139/cjfr-2020-0217 · 被引用次数：3 · 研究领域：Plant Water Relations and Carbon Dynamics、Tree-ring climate responses、Climate variability and models

Given the large contribution of forests to terrestrial carbon storage, there is a need to resolve the environmental and physiological drivers of tree-level response to rising atmospheric CO 2 . This study examines how site-level soil moisture influences growth and intrinsic water-use efficiency in sugar maple (Acer saccharum Marsh.). We construct tree-ring, δ 18 O, and Δ 13 C chronologies for trees across a soil moisture gradient in Ontario, Canada, and employ a structural equation modelling approach to ascertain their climatic, ontogenetic, and environmental drivers. Our results support previous evidence for the presence of strong developmental effects in tree-ring isotopic chronologies — in the range of −4.7‰ for Δ 13 C and +0.8‰ for δ 18 O — across the tree life span. Additionally, we show that the physiological response of sugar maple to increasing atmospheric CO 2 depends on site-level soil moisture variability, with trees only in relatively wet plots exhibiting temporal increases in intrinsic water-use efficiency. These results suggest that trees in wet and mesic plots have experienced temporal increases in stomatal conductance and photosynthetic capacity, whereas trees in dry plots have experienced decreases in photosynthetic capacity. This study is the first to examine sugar maple physiology using a dendroisotopic approach and broadens our understanding of carbon–water interactions in temperate forests.