Objective  In order to quantitatively evaluate the eco-hydrological effects of forest litter layer in Xishan Mountain of Beijing, the study quantified the eco-hydrological process of litter layer from the aspects of litter storage, thickness, water holding capacity and interception capacity.

  Method  From 2020−2021, four typical artificial forest stands (Pinus tabuliformis, Quersus variabilis, Platycladus orientalis and Acer truncatum) with approximately similar altitude, slope, aspect, position, stand age and density were selected for the study. The structure and eco-hydrological characteristics of each type of litter layer were analyzed by field measurement, indoor immersion experiment and indoor artificial simulated rainfall experiment, so as to realize the quantitative expression of eco-hydrological effects of typical artificial forest stand litter layer.

  Result  (1) The storage range of litter layer was 2.12−8.27 t/ha, and the thickness range was 2.09−8.69 cm, all showed that the litter of Quercus variabilis was the largest and that of Platycladus orientalis was the smallest. (2) The total maximum water holding capacity of all types of litter without stratification was 21.20 t/ha for Quersus variabilis, 17.30 t/ha for Acer truncatum, 5.32 t/ha for Pinus tabuliformis and 3.88 t/ha for Platycladus orientalis. The maximum water holding capacity of coniferous and broadleaved litter was different and significantly different (P < 0.05). (3) The mean value of maximum interception capacity of coniferous litter was 2.43 mm, and that of broadleaf litter was 3.25 mm. The mean value of minimum interception capacity of coniferous litter was 2.26 mm, and that of broadleaf litter was 2.99 mm. Both maximum interception capacity and minimum interception capacity of each type of litter layer increased with the increase of rain intensity, however, there was a significant difference in interception capacity between coniferous and broadleaf litter (P < 0.05). (4) With the gradual increase of rain intensity, the proportion of 1 h water holding capacity in the corresponding maximum interception capacity and minimum interception capacity of all types of litter decreased gradually.

  Conclusion  Among the four typical artificial forest stands in Xishan Mountain of Beijing, the interception capacity of litter layer of Quersus variabilis forest was maximum, while that of Platycladus orientalis was minimum, and broadleaved forests as a whole are larger than coniferous forests. Therefore, it is suggested that the study area should reasonably optimize the composition of tree species and the configuration of forest structure, give consideration to the prevention and control of soil erosion and forest moisture, and reduce ineffective transpiration, so as to achieve the overall improvement of ecological and hydrological functions. Therefore, it is suggested that the study area should reasonably optimize the composition of tree species and the configuration of forest structure, give consideration to the prevention and control of soil erosion and forest moisture, and reduce ineffective transpiration, so as to achieve the overall improvement of ecological and hydrological functions.ecological and hydrological functions.Therefore, it is suggested that the tree species composition and stand structure configuration of the study area be reasonably optimized, taking into account the prevention of soil erosion and stand wetting, and reducing ineffective transpiration, so as to achieve an overall improvement of eco-hydrological function.