Study On Structural Adjustment Of Wrater Source Forest In Fengning County Of Northern Hebei Province

For the purpose that the adjustment of young forest structure in the study area,four kinds of water source forest land were selected as the research object in Fengning County in northern Hebei.Taking the main factors affecting the benefit of ecological function of water source forest land into account,the paper focused on the role soil layer and litter layer playing in water conservation,and analysed GIS-based spatial heterogeneity of soil nutrients in different water source forest land in the sight of basin scale.this paper explored the way to maximize the effectiveness of ecological function in forest by using the analytic hierarchy process to explore how to construct the proportion of the four kinds of water source forest types,then put forward the ideal structure.The thesis are summarized as follows:(1)Taking different site types into comprehensive comparison,the poplar forest has the strongest water conservation capacity on the soil layer and litter layer,and the maximum water holding capacity and water holding capacity were 1334.49 and 1167.41t/hm2,the overall water conservation ability follows the order:the poplar land>Larch xPrunus armeniaca forest land> Pinus tabulaeformis×Prunus armeniaca forest land>Pinus tabulaeformis land.(2)The difference of soil water nutrient content under different forest types is great difference. From the range of soil nutrient content and the average value,the content and distribution of soil nutrient content generally follow as:the poplar land>Larch xPrunus armeniaca forest land>Pinus tabulaeformisxPrunus armeniaca forest land>Pinus tabulaeformis land.(3) From the angle of analysis on the difference of water conservation capacity and soil nutrient content in the water source forest land,Ecological function capacity of different water source forests is significantly different.Under the condition of the same site,broadleaf conifer mixed forest has better ecological function.In order to give full play to the water conservation function of the water conservation forest in the northern Hebei area, we should strengthen the operation and management of the existed water source forest,and construct the reasonable structure of water conservation forest.(4)In order to give full play to ecological function capacity of water source forest stand structure,the reasonable stand structure is as follows,15.01% of the stand structure is Pinus tabulaeformis forest land,22.93% of the structure is Pinus tabulaeformis xPrunus armeniaca forest land,larch xrunus Armeniaca forest land account for 27.46%,and the ratio of Populus forest land area is 34.61%.