基于坐标评定法的京西水源保护林枯落物及土壤水文效应综合评价

Comprehensive Evaluation of Litter and Soil Hydrological Effects of Water Source Protection Forest in Western Beijing Based on Coordinate Evaluation Method

为探究北京西部水源保护林森林水文功能,选择该区域常见的油松、山杨、白桦和华北落叶松4种纯林,利用坐标评定法对其水文效应进行综合评价。结果表明:(1)枯落物蓄积量排序为油松林(8.90 t·hm^(-2))>华北落叶松林(6.35 t·hm^(-2))>山杨林(5.66 t·hm^(-2))>白桦林(5.05 t·hm^(-2));枯落物最大持水量排序为华北落叶松林(46.79 t·hm^(-2))>油松林(37.19 t·hm^(-2))>白桦林(26.27 t·hm^(-2))>山杨林(21.85 t·hm^(-2));半分解层最大持水量大于未分解层。(2)土壤总孔隙度排序为白桦林(60.10%)>油松林(59.18%)>山杨林(54.20%)>华北落叶松林(48.77%),土壤层最大持水量排序为白桦林(3650.70 t·hm^(-2))>油松林(3550.98 t·hm^(-2))>山杨林(3252.00 t·hm^(-2))>华北落叶松林(2926.20 t·hm^(-2))。(3)林地总最大持水量排序为白桦林(3676.97 t·hm^(-2))>油松林(3558.17 t·hm^(-2))>山杨林(3273.85 t·hm^(-2))>华北落叶松林(2972.99 t·hm^(-2)),土壤层的最大持水量远大于枯落物层。(4)用坐标评定法对4种林分水文效应综合评价结果排序为油松林、华北落叶松林、山杨林、白桦林,针叶林优于阔叶林。

In order to explore the hydrological function of water source protection forest in western Beijing,in this paper,four pure forests including Pinus tabulaeformis,Populus davidiana,Betula platyphylla and Larix principis-rupprechtii in western Beijing were selected and the hydrological effects of the four stands were comprehensively evaluated by coordinate evaluation method.The results showed as the following four parts.(1)The order of litter volume was Pinus tabulaeformis forest(8.90 t·hm^(-2))>Larix principis-rupprechtii forest(6.35 t·hm^(-2))>Populus davidiana forest(5.66 t·hm^(-2))>Betula platyphylla forest(5.05 t·hm^(-2));the maximum water holding capacity of litter was Larix principis-rupprechtii forest(46.79 t·hm^(-2))>Pinus tabulaeformis forest(37.19 t·hm^(-2))>Betula platyphylla forest(26.27 t·hm^(-2))>Populus davidiana forest(21.85 t·hm^(-2)).The maximum water holding capacity of semi-decomposed layer was larger than that of undecomposed layer.(2)The order of total porosity of soil was Betula platyphylla forest(60.10%)>Pinus tabulaeformis forest(59.18%)>Populus davidiana forest(54.20%)>Larix principis-rupprechtii forest(48.77%).The maximum water holding capacity of soil was Betula platyphylla forest(3650.70 t·hm^(-2))>Pinus tabulaeformis forest(3550.98 t·hm^(-2))>Populus davidiana forest(3252.00 t·hm^(-2))>Larix principis-rupprechtii forest(2926.20 t·hm^(-2)).(3)The order of the total maximum water holding capacity of the forest land was Betula platyphylla forest(3676.97 t·hm^(-2))>Pinus tabulaeformis forest(3558.17 t·hm^(-2))>Pinus tabulaeformis forest(3273.85 t·hm^(-2))>Larix principis-rupprechtii forest(2972.99 t·hm^(-2)).The maximum water holding capacity of the soil layer was much greater than that of the litter layer.(4)The results of the comprehensive evaluation of hydrological effects of the four kinds of stands by the coordinate evaluation method were ranked as follows:Pinus Tabulaeformis forest,Larix principis-rupprechtii forest,Populus davidiana forest,Betula platyphylla forest;and coniferous forest was superior to broad-leaved forest.