Finding balance: Tree‐ring isotopes differentiate between acclimation and stress‐induced imbalance in a long‐term irrigation experiment

作者：Valentina Vitali, Philipp Schuler, Meisha Holloway‐Phillips, Petra D’Odorico, Claudia Guidi, Stefan Klesse, Marco M. Lehmann, Katrin Meusburger, Marcus Schaub, Roman Zweifel, Arthur Geßler, Matthias Saurer · 发表于：Global Change Biology · 年份：2024 · DOI：10.1111/gcb.17237 · 被引用次数：13 · 研究领域：Plant Water Relations and Carbon Dynamics、Tree-ring climate responses、Forest ecology and management

Abstract Scots pine ( Pinus sylvestris L.) is a common European tree species, and understanding its acclimation to the rapidly changing climate through physiological, biochemical or structural adjustments is vital for predicting future growth. We investigated a long‐term irrigation experiment at a naturally dry forest in Switzerland, comparing Scots pine trees that have been continuously irrigated for 17 years ( irrigated ) with those for which irrigation was interrupted after 10 years ( stop ) and non‐irrigated trees ( control ), using tree growth, xylogenesis, wood anatomy, and carbon, oxygen and hydrogen stable isotope measurements in the water, sugars and cellulose of plant tissues. The dendrochronological analyses highlighted three distinct acclimation phases to the treatments: irrigated trees experienced (i) a significant growth increase in the first 4 years of treatment, (ii) high growth rates but with a declining trend in the following 8 years and finally (iii) a regression to pre‐irrigation growth rates, suggesting the development of a new growth limitation (i.e. acclimation). The introduction of the stop treatment resulted in further growth reductions to below‐control levels during the third phase. Irrigated trees showed longer growth periods and lower tree‐ring δ 13 C values, reflecting lower stomatal restrictions than control trees. Their strong tree‐ring δ 18 O and δ 2 H (O–H) relationship reflected the hydrological signature similarly to the control. On the cont...