The redistribution of rainfall in mixed coniferous-broadleaf forests: The combined effect of rainfall characteristics and stand structure

Water scarcity and its uneven distribution are two major environmental issues faced today, and water is a key element in maintaining the balance and stability of forest ecosystems. With the continuous changes in precipitation patterns and the introduction of broadleaf species, the forest-water relationship has become increasingly complex, and coordinating this relationship has become a new challenge in addressing global climate alters. To elucidate how the interaction between rainfall characteristics and forest structure changes hydrological processes and water resource availability, this study focused on three distinctly different forest types in the state-owned Longli National Forest Farm in Guizhou Province: P. massoniana forest, P. massoniana–Manglietia conifera forest, P. massoniana–Cercidiphyllum japonicum forest. By quantifying rainfall redistribution in the canopy and litter layers and analyzing rainfall characteristics and forest structure, the study finds that compared to pure coniferous forests, mixed conifer-broadleaf forests increase precipitation allocation to stemflow (87.74%) and canopy interception (53.08%), while reducing allocation to throughfall (22.94%). Among these factors, stand density (SD), leaf area (LA), and leaf area index (LAI) regulate water pathways, whereas rainfall amount and duration determine water sources. Together, these elements influence rainfall redistribution, resulting in increased precipitation entering the soil. Therefore, when constructing mixed conifer–broadleaf forests, it is essential to manage SD, LA, LAI, and leaf and bark morphology to reduce soil moisture deficits, maintain forestland sustainability, and create an efficient ecosystem.