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枯枝落叶作为森林生态系统中净第一性生产力的重要组成部分,是物质循环过程中的一个物质库,起着涵养水分,减少地表蒸发,改善土壤肥力,防止水土流失的重要作用。油松(Pinus tabulaeformis)和侧柏(Platicladus orientalis)是我国北方山区防护林的主要造林树种,目前多为人工纯林。这种针叶纯林一般生长缓慢,郁闭较迟,保持水土的能力也较差,并易受自然灾害的影响,从而不能有效地
As an important component of net primary productivity in forest ecosystem, litter is a material bank in the process of material circulation, playing an important role in water conservation, surface evaporation reduction, soil fertility improvement and soil erosion prevention. Pinus tabulaeformis and Platicladus orientalis are the main afforestation species in the mountainous shelterbelts in northern China. At present, most of them are artificial pure forests. This coniferous pure forest generally grows slowly, closes later, has less ability to retain soil and water and is susceptible to natural disasters, and thus can not effectively