托木尔峰自然保护区台兰河上游森林植被水源涵养功能

Water Conservation Function of Forest Ecosystems in the Upper Tailan River in the Mount Tumor Nature Reserve

为定量评价托木尔峰自然保护区森林的水源涵养能力,利用综合蓄水能力法,对台兰河上游雪岭云杉森林生态系统的林冠层截留量(C)、枯枝落叶层持水量(L)、土壤层蓄水量(S)及综合水源涵养能力进行估算和分析。结果表明:(1)研究区4样地中,林冠层截留量表现为中海拔云杉林(29.94mm)>较高海拔云杉林(20.56mm)>高海拔云杉林(11.72mm)>低海拔云杉杨树混交林(5.84mm),而茎流量则与之相反。(2)除中海拔云杉林外,各样地枯枝落叶未分解层平均厚度均大于半分解层;其中,未分解层的平均蓄积量中高海拔云杉林最大(79.32t/hm^2),半分解层为中海拔云杉林最大(59.47t/hm^2)。整体来看,枯枝落叶层的最大持水量大小依次为中海拔云杉林(32.55mm)>高海拔云杉林(31.05mm)>较高海拔云杉林(30.78mm)>低海拔云杉杨树混交林(12.84mm)。(3)4样地平均土壤容重变动范围为0.73~1.06g/cm^3;土壤孔隙度的平均值大小均为中海拔云杉林>较高海拔云杉林>高海拔云杉林>低海拔云杉杨树混交林;林下土壤自然含水率随海拔高度的增加呈不断上升趋势。不同样地30cm深土层的非毛管孔隙持水量表现为:中海拔云杉林(37.6mm)>较高海拔云杉林(30.7mm)>高海拔云杉林(25.73mm)>低海拔云杉杨树混交林(13.92mm)。(4)研究区森林生态系统的水源涵养能力在171.27~280.84mm之间,低海拔云杉杨树混交林的总持水量最小,中海拔云杉林最大。土壤层水源涵养贡献率最大,占比在77.75%~89.10%之间;总有效蓄水量虽远小于总持水量,但能够很好地发挥水源涵养功能和水土保持作用。

To evaluate the water conservation capacity of forests in the Mount Tumor Nature Reserve quantitatively,comprehensive water storage capacity method was used to investigate the canopy interception capacity（C）,litter water-holding capacity（L）,soil water storage capacity（S）of Picea schrenkiana forest ecosystems in the upper Tailan River,then a comprehensive evaluation of its water conservation function was made.The results showed that：（1）In the four sample areas,the canopy interception capacity followed the order og the middle altitude spruce forest（29.94mm） 〉higher altitude spruce forest（20.56mm）〉 high altitude spruce forest（11.72mm）〉low altitude mixed broad leaf-conifer forest（5.84mm）,and the stem flow showed the opposite order.（2）Except for the middle altitude spruce forest,the average thickness of un-decomposed litter was thicker than that of the intermediately decomposed layer.The high altitude spruce forest had the largest average volume of decomposed layer（79.32t/hm^2）,while the middle altitude spruce forest had the largest intermediately decomposed layer（59.47t/hm^2）.On the whole,the rank of the maximum water holding capacity was the middle altitude spruce forest（32.55 mm）〉 the high altitude spruce forest（31.05mm）〉the higher elevation spruce forest（30.78mm） 〉the low altitude mixed broad leafconifer forest（12.84mm）.（3）Soil bulk density in the four sampled forests ranged from 0.73g/cm^3 to 1.06g/cm^3.Both the average soil porosity and water holding capacity of capillary pore in the 30 cm soil layer were in the order of the middle altitude spruce forest〉the higher altitude spruce forest〉the high altitude spruce forest〉the low altitude mixed broad leaf-conifer forest.Overall,soil moisture content of natural forests increased with the increase of the altitude.The average water holding capacity of non-capillary pore in the 30 cm soil layer followed the order of the middle altitude spruce forest（37.6mm）〉the higher altitude spruce forest（30.7mm）〉the high altitude spruce forest（25.73mm）〉the low altitude mixed broad leaf-conifer forest（13.92 mm）.（4）Comprehensive water conservation capacity of the forest ecosystems in the study area was bwteen 141.12 and 280.84 mm,with the low altitude mixed broad leaf-conifer forest and the middle altitude spruce forest having the smallest and largest water holding capacity,respectively.The soil layer contributed the most to water conservation,accounting for 77.75%-86.96%.Comprehensive effective water storage capacity was far less than the theoretical total capacity,but could work well in the water conservation function as well as water and soil conservation effect.