北川河流域典型林型水源涵养能力评价

Evaluation on water conservation capacity of typical forest types in Beichuan River basin

森林是水源涵养功能的基础和载体,青海省北川河流域森林覆盖较好,但当前流域内林地的水源涵养情况尚不清楚。本研究选取青海云杉、白桦、华北落叶松、沙棘和青杨这5种在流域内典型树种,对林冠层、枯落物层和土壤层的10个与水源涵养功能密切相关的指标进行流域森林水源涵养分析评价,同时采用层次分析法获得各林种和各指标的权重。结果显示:在林冠层的比较中,青海云杉和白桦的水源涵养能力最佳,华北落叶松次之,沙棘和青杨居末;但在枯落物层的比较中,华北落叶松、白桦和青海云杉的水源涵养能力较好,青杨居中,沙棘表现最差;而在土壤层的比较中,青海云杉和白桦同样水源涵养能力较好,沙棘居中,青杨和华北落叶松较弱。同时,在利用层次分析法检验得到:青海云杉权重最高,达到25%,另外土壤层的水源涵养能力占林冠、枯落物和土壤这3层比重最大,为70.51%。综合林冠、枯落物、土壤和层次分析比较结果,当前水源涵养能力排序为:青海云杉林地>白桦林地>华北落叶松林地>沙棘林地>青杨林地。这一结果为进一步讨论流域内植被景观格局和空间优化配置提供了参考和理论依据。

[Background]Forest is an indispensable part of human survival.Forest water conservation capacity is an important part in searching ecological benefits.In Beichuan River basin,Qinghai Province,since the policy‘Converted Farmland into Forest爷implemented,it has protected forest land and improved froest coverage.Due to less research of forest water conservation in basin,the effect of forest water conservation in whole basin is unknown yet.We aimed to discuss the regulation of vegetation,in order to maximize basin forest ecological benefits.[Methods]In order to explore water conservation capacity of forest in Beichuan River basin,Qinghai Province,we chose five typical tree species:Picea crassifolia,Betula platyphylla,Larix principis rupprechtii,Hippophae rhamnoides and Populus cathayana,to analyse and evaluate10indexes which are closely related to water conservation from the forest canopy layer,litter layer and soil layer,meanwhile adpoted the analytic hierarchy Process(AHP)to analyze the proportion of these woodlands and indexes in water conservation.