Study On Water Conservation Capacity Of Forest System In The Upper Reaches Of East Liao River Basin Of Jilin Province

Recently, the lack of water resources and the deterioration of water qualityspread around the world,the function of water conservation of forest ecosystem isgetting more attentions. Forest ecosystem conserves rainfall by crown, litter layer andsoil layer. Many districts have conducted constructions of water conservation forest toimprove the water conservation ability and reduce water loss and soil erosion.East Liao River is a main tributary of Liao River. The upper reaches of East LiaoRiver is source of Liao River. The water conservation ability of forest ecosystem inthis area has great influences on water supply of Liao River. The study Improve theability of river basin water conservation and integrations and demonstrations ofpollutants intercept technology affiliated to the fourth content of national majorprojects of water pollution control and management——Liao River basin of JilinProvince ecological security technology research and demonstration. Based onForest Hydrology, Hydrology, Water Resources and Soil Science, investigating thestatus of forest resources in East Liao River upstream districts and using the fieldinvestigation and laboratory analysis method, carry out the research on forestecosystem water conservation function in upstream East Liao River. From thewater-holding ability of crown layer and the litter layer and the water storage andpermeability of soil layer, position observation, calculation, analysis were taken toevaluate the water conservation functions of the study area.Forest canopy interception of different vegetation was calculated by the amountof the rainfall, through fall and the trunk sap flow. The results show: Among the fourdifferent vegetation types, the order of water conservation ability of forest canopyinterception was larch forests, artificial coniferous forests, coniferous andbroad-leaved mixed forest and the poplar-birch forest. The amount of forest canopyinterception related to crown density and their own characteristics. Forest canopyinterception of coniferous forests were much higher than broad-leaved forests.Comparing and analyzing the water conservation ability of litter layer of thedifferent vegetation types, we may draw conclusions：Thickness of litter layer of thedifferent vegetation types range from3.04cm to5.25cm. Thickness of broad-leaved forests tends to be higher than coniferous forests. The possible factors are shown asfollows. Firstly, broad-leaved forests have more litters. Secondly, the leaves have abigger area. Also, there were many gaps in the leaves. Reserves of coniferous forestsare much more than broad-leaved forests. The reason is that litters of coniferousforests decompose slowly. The order of water conservation ability of litter layers islarch forests, coniferous and broad-leaved mixed forest, artificial coniferous forestsand the poplar-birch forests.Research of soil moisture content, physical properties and water-holding abilitiesshowed that: Soil moisture content of different vegetation types decreased with theincrease of soil depth. Soil moisture content of larch forests and artificial coniferousforests were higher than coniferous forests and coniferous and broad-leaved mixedforests. The order of soil porosity is the poplar-birch forests, coniferous andbroad-leaved mixed forests, artificial coniferous forests and coniferous forests. Bothsoil porosity and soil capillary porosity of the poplar-birch forests and the coniferousand broad-leaved mixed forests were higher than the other two vegetation types. Assoil water-holding abilities were depended on the capillary porosity of forest soil, theorder of soil water-holding abilities is the poplar-birch forests, coniferous andbroad-leaved mixed forests, coniferous forests and artificial coniferous forests. Ingeneral, soil of the poplar-birch forests has the highest water-holding abilities andeffective water-holding abilities among the four vegetation types.Through this study, the forest ecosystem water conservation abilities werecomprehensively evaluated. Not only the amount of water conservation has beencalculated, the water conservation abilities of the different vegetation types were alsocompared. It’s helpful for understanding the hydrology process and its principle. Theresults of the paper provided data support to evaluate the water conservation functionand theoretical foundation for reasonable use of water resource and protection of theecological environment.