Influence of stand density on water-holding characteristics of litter layer | 林分密度对枯落物层持水特性的影响

صينى. 探讨林分密度对枯落物层持水特性的影响。以燕山山地不同林分密度(650(40年生)，1 400(35年生)，1 850(38年生)株/hm2)的油松人工林为研究对象，在其下设置标准地，测定枯落物层厚度和蓄积量，并将枯落物带回，采用室内浸泡法测定不同林分密度下枯落物层的持水特性。3种密度油松人工林枯落物层蓄积量为26.62～49.79 t/hm2；在林龄相差不大的情况下，650，1 400和1 850株/hm2油松人工林枯落物层蓄积量与林分密度呈现正相关关系。油松人工林枯落物层自然含水量随林分密度变化不明显，在50%左右；3种密度林分的饱和持水率无明显的规律性。枯落物层持水量与浸水时间呈对数关系；吸水速率与浸水时间呈幂函数关系。枯落物层对降雨的拦蓄能力与其林分密度呈正相关关系。对于林龄接近、立地条件相似的油松人工林而言，密度越大，其林下枯落物总蓄积量越大，枯落物层对于降雨的拦蓄作用也越强。

إنجليزي. This paper is to discuss the influence of stand density on litter water-holding characteristics. Take Pine plantations of different stand densities ((650(40a), 1 400(35a),1 850(38a)/hm2)) in Yanshan Mountain as the research object, we set standard plots, measured the depth and accumulation volume of the litter and brought these litters back, and used indoor immersion method to measure litter water-holding characteristics under different stand densities. Litter’s accumulation volume of these pine plantations is 26.62-49.79 t/hm2. If stand age is not the case, litter accumulation and stand density will show a positive correlation in density of 650, 1 400, 1 850 plant/hm2. The natural moisture content of Pinus tabulaeformis forest plantation in this study is around 50% and it does not change significantly with stand density, while saturated water-holding rate does not show any obvious regularity with stand density. Water-holding capacity of litter and soaking time have logarithmic relationship, while the relationship of water absorption rate and soaking time is power function. Litter’s ability to intercept and accumulate rainfall is positively associated with stand density. For those Pinus tabulae formis forest plantation with similar age and standing conditions, both accumulation volume of litter and its capacity of intercepting rainfall will be much greater as stand density increases.