Опубликована: Окт. 12, 2023

Abstract. While reforestation in water-limited areas has increased vegetation coverage, an increasing number of studies have reported that large-scale plantations are suffering from tree degradation, which is characterized by short trees, small size, and dieback. Moreover, the changes hydrological processes degraded trees within soil-plant system remain poorly understood. Here, stable isotope method (²H, ¹⁸O, ¹³C) thermal dissipation technique were used to compare soil water dynamics, transpiration, root uptake patterns, intrinsic water-use efficiency (WUE_i) Populus simonii under different degradation degrees (no ND; light LD; or severe SD) 2021 growing season. As intensified, weight density decreased significantly (P<0.05) proportion shallow layer (0–40 cm) increased. Influenced precipitation recharge, volumetric content (SWC) did not show significant differences (P>0.05) among degrees. The SWC middle (40–80 deep (80–200 layers lower ND plot than LD SD plots. Despite SWC, isotopic characteristics xylem similar ND, LD, Although transpiration plots was reduced compared plot, main depths proportions change. P. able shift source process wetting drying. healthy WUE_i more sensitive SWC. Our study shows although alleviate exhaustion reservoirs some extent, sustainable development afforestation ecosystems requires appropriate stand management measures maintain balanced forest-water relationships.