基于多级可拓法的抚育间伐强度对测树因子影响效果评价

Evaluation on the effect of thinning intensity on the tree-measurement factors based on multi-level extension method

【目的】探讨最适合小兴安岭区域天然针阔混交林林木生长的抚育间伐强度,为小兴安岭地区的森林抚育间伐提供参考。【方法】研究对象为2011年在带岭林业实验局东方红林场建立的不同抚育间伐强度的天然针阔混交林样地:CK(抚育间伐强度为0%)、A(10%)、B(15%)、C(20%)、D(25%)、E(30%)、F(35%),基于2019年外业调查的优势树种(冷杉、青楷槭、红松、云杉、椴树、色木槭、水曲柳)的测树因子(胸径、树高、冠长、冠幅)数据,建立了小兴安岭区域抚育间伐效果评价标准,构建了抚育间伐效果多级可拓评价模型,用层次分析法确定了评价模型中各指标的权重,通过关联函数计算各样地关于评价标准的关联度,确定了各样地的抚育间伐效果可拓等级。【结果】各样地的抚育间伐效果可拓等级为:Ⅳ[CK(0%)]、Ⅲ[A(10%)]、Ⅳ[B(15%)]、Ⅳ[C(20%)]、Ⅲ[D(25%)]、Ⅱ[E(30%)]、Ⅲ[F(35%)];B、C样地的可拓等级与对照样地CK相当,表明15%、20%的抚育间伐强度对林木生长水平的提升不显著;A、D、E、F样地的可拓等级高于对照样地CK,表明10%、25%、30%、35%的抚育间伐强度均会提高样地的抚育间伐效果,可一定程度上提升林木的生长水平;C、D、E、F样地的抚育间伐效果等级呈现出明显的先提升后下降的趋势,E样地的抚育间伐效果等级最高,为Ⅱ级,表明小兴安岭区域最适合林木生长的抚育间伐强度为30%。【结论】构建的多级可拓评价模型可有效的确定小兴安岭区域森林抚育间伐效果等级,30%的抚育间伐强度最有利于小兴安岭天然针阔混交林乔木层的生长。

【Objective】To explore the optimal forest thinning intensity for the growth of natural mixed broadleaf-conifer forest in Xiaoxing’ an mountains of northeastern China, and to provide references for forest thinning in Xiaoxing’ an mountains.【Method】The research object is natural mixed broadleaf-conifer forest sample plots with different thinning intensities established in the Dongfanghong forest farm of Dailing Forestry Experimental Bureau in 2011: CK( thinning intensity was 0%), A(10%), B( 15%), C(20%), D(25%), E(30%), F(35%), based on the date of tree-measurement factors(Diameter at breast height, tree height, crown height, crown width) of dominant tree species(Abies fabri, Acer tegmentosum, Pinus koraiensis, Picea asperata, Tilia tuan, Acer pictum, Fraxinus mandshurica) in the field survey in 2019, established the evaluation standard for the effect of thinning in Xiaoxing’an mountains, and constructed a evaluation model of multi-level extension for the effect of thinning. The analytic hierarchy process was used to determine the weight of each index in the evaluation model, and the relevance degree of each sample plot with respect to the evaluation standard was calculated through the dependent function, and each sample plot’s multi-level extension grade of the effect of thinning was determined. 【Result】The sample plots’ multi-level extension grades of the effect of thinning are: Ⅳ[CK(0%)], Ⅲ[A(10%)], Ⅳ[B(15%)], IV[C(20%)], Ⅲ[D(25%)], Ⅱ[E(30%)], Ⅲ(35%)], the extension grades of B and C sample plots are equivalent to the control sample plot(CK), indicating the thinning intensity of 15% and 20% does not significantly increase the growth level of forest trees;the extension grades of A, D, E, and F plots are higher than the control sample plot(CK), indicating that the thinning intensity of 10%, 25%, 30%, and 35% will all increase the thinning effect of sample plots, to improve the growth level of forest trees to a certain extent;the thinning effect grades of sample plots C, D, E, and F show an obvious trend of first increasing and then decreasing, and the thinning effect grades of sample plot E is the highest--being grade Ⅱ, indicates that the optimum thinning intensity that most suitable for forest growth in Xiaoxing’ an mountains of northeastern China is 30%.【Conclusion】The constructed multi-level extension evaluation model can effectively determine the grade of the effect of thinning in Xiaoxing’ an mountains. The thinning intensity of 30% is most conducive to the growth of natural mixed broadleaf-conifer forest in Xiaoxing’ an mountains.