Unraveling the age-dependent water use strategy and its drivers in fast-growing balsa wood (Ochroma lagopus) plantations

Yuan, Xia

AGRICULTURAL AND FOREST METEOROLOGY

2026

386

Yang, B; Zhu, XI

Understanding water use strategies and their underlying drivers in artificial plantations is crucial for developing effective forest management practices. Balsa wood (Ochroma lagopus) is one of the fastest-growing economic plantation species and is in substantial international demand. However, the dynamics of its water use strategies and physiological adaptations remain poorly understood. In this study, we investigated balsa stands of different ages (1-, 2-, 3-and 4-yr) to examine their water uptake patterns and long-term intrinsic water use efficiency (WUEi) using a multi-isotope approach (62H, 618O, 613C, and 615N) combined with leaf nutrient traits (N and P concentrations). The results showed that 1-and 2-year-old balsa stands primarily extracted water from the 20-50 cm soil layer (accounting for 41.1-41.7% of total uptake), whereas 3-and 4-year-old stands relied more heavily on the 0-20 cm layer (52.5-58.5%). Age-related attributes (e.g., DBH, tree height, and root traits) and soil available phosphorus (AP) were the primary drivers of these dynamics. Balsa wood exhibited an age-related shift from a conservative to a more opportunistic water-use strategy, adapting to seasonal drought primarily through adjustments in WUEi rather than altering uptake depth. Furthermore, 613C showed significant negative correlations with leaf C/P and C/N ratios, indicating a clear trade-off between water-use efficiency and nutrient-use strategy. These findings demonstrate that soil AP serves as a key factor shaping water uptake patterns and provide new insights into the water-use dynamics of fast-growing economic plantations and their adaptive mechanisms under resource-limited conditions.