Hydrological Effects of Litter and Soil Layers in Different Forest Stands in Mountainous Areas of the Zhejiang–Jiangxi Border Region, China

This study examined four forest stands (Pseudotsuga gaussenii Flous, Quercus glauca Thunb., Pinus taiwanensis Hayata and Rhododendron simiarum Hance forests) in the Huaiyu Mountain Range at the Jiangxi–Zhejiang border in China and systematically compared their litter stocks, water-holding characteristics, soil hydro-physical properties, and infiltration characteristics through field investigation, the cutting-ring method, and the indoor soaking method. The results were as follows: (1) The total litter stock ranged from 4.64 to 8.35 t·ha−1, being highest in the R. simiarum forest and lowest in the Q. glauca forest. (2) The litter maximum water-holding capacity (2.92–5.92 t·ha−1) and effective water-retention capacity (1.56–3.30 t·ha−1) differed significantly among stands (p < 0.05), with the P. gaussenii forest performing well and the P. taiwanensis forest performing the worst. (3) In the 0–30 cm soil layer, bulk density increased with depth, while total porosity and water-holding capacity decreased significantly (p < 0.05), and the infiltration rate showed a power-function relationship with time (R2 > 0.95); among the four forest types, the R. simiarum forest exhibited the highest maximum and capillary soil water-holding capacities, the Q. glauca forest had the strongest infiltration and runoff-interception capacity, and the P. taiwanensis forest had the weakest overall soil hydrological performance. (4) Semi-decomposed litter had a significantly higher maximum water-holding capacity than undecomposed litter, and litter water-holding capacity and water absorption rate showed logarithmic and power-function relationships with soaking time, respectively (both R2 > 0.90). A comprehensive evaluation using the entropy weight method identified the P. gaussenii and Q. glauca forests as the superior stand types. These results provide scientific guidance for tree species selection in forest transformation and for sustainable forest management in this region.