北京松山4种典型林分枯落物持水特征研究

Study on Water Holding Characteristics of Four Typical Forest Litter in Songshan,Beijing

为研究北京松山国家自然保护区不同林分枯落物持水效能差异,采用典型样地调查和室内浸泡法,对松山国家级自然保护区内4种典型林分类型,即蒙古栎(Quercus mongolica)纯林、油松(Pinus tabuliformis)纯林、山杨(Populus davidiana)纯林和毛白杨(Populus tomentosa)-油松针阔混交林的枯落物水文效应进行分析。结果表明,(1)4种典型林分类型枯落物层蓄积量为8.05—23.78 t·hm^(−2),大小排序为蒙古栎纯林(23.78 t·hm^(−2))>山杨纯林(21.26 t·hm^(−2))>油松纯林(15.85 t·hm^(−2))>针阔混交林(8.05 t·hm^(−2))。(2)山杨纯林枯落物最大持水量最大(7.19 t·hm^(−2)),蒙古栎纯林最小(4.37 t·hm^(−2));比较4种典型林分类型枯落物平均持水率发现,针阔混交林最大(230.9%),蒙古栎纯林最小(106.85%)。(3)4种林分枯落物层持水量与其浸水时间呈对数相关(R2>0.75,P<0.01);其持水速率与浸泡时间符合幂函数关系(R2>0.89,P<0.01)。山杨纯林有效拦蓄量(13.67 t·hm^(−2))与有效拦蓄率(114.3%)均较高,而油松纯林有效拦蓄量(4.46 t·hm^(−2))及其有效拦蓄率(58.11%)均显著低于其他林分类型。根据水文指标评价上述4种典型林分枯落物持水能力,松山自然保护区内山杨纯林枯落物持水能力最佳,其水源涵养综合能力优于其他3种类型林分枯落物。研究结果可为区域植被恢复和水土流失防治提供理论基础。

Four typical forest stands including three pure forests i.e.Quercus mongolica,Pinus tabulaeformis,and Populus davidiana and mixed forest of Populus tomentosa and Pinus tabulaeformis in Songshan National Nature Reserve of Beijing were selected to evaluated their hydrological capacities in litter layers through typical field investigation and indoor immersion timing treatments.The results showed that(1)the litter accumulation volumes in four typical forest stands ranged from 8.05 t·hm^(−2) to 23.78 t·hm^(−2).The litter accumulation volume was sorted as Quercus mongolica pure forest(23.78 t·hm^(−2))>Populus davidiana pure forest(21.26 t·hm^(−2))>Pinus tabulaeformis pure forest(15.85 t·hm^(−2))>coniferous and broad-leaved mixed forest(8.05 t·hm^(−2)).(2)The maximum water holding capacity of litter layer in Populus davidiana pure forest(7.19 t·hm^(−2))was the largest,and those in Quercus mongolica pure forest(4.37 t·hm^(−2))was the smallest than that in other forest stands.Comparing the average water holding capacity of the litter layer in four typical forest stands,it was found that the coniferous and broad-leaved mixed forest was the largest(230.90%),whereas the smallest one was observed in Quercus mongolica pure forest(106.85).(3)There was a logarithmic correlation between the water holding capacity of litter layer and the immersion time(R2>0.75,P<0.01),while water holding rate of litter layer and immersion time could be fitted by power function(R2>0.89,P<0.01).The effective storage capacity(13.67 t·hm^(−2))and its rate(114.3%)of litter layer in Populus davidiana pure forest were higher than that in other stands,while those capacity(4.46 t·hm^(−2))and its rate(58.11%)of litter layer in Pinus tabulaeformis pure forest were remarkable lower than other forest stands.According to the above-mentioned hydrological indicators,the synthetic water conservation capacity of litter layer in Populus davidiana pure forest is better than that in other three types of forest litter.This study can provide a theoretical basis for specific regional vegetation restoration and soil erosion control.