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粗木质残体 (CWD)对于长江上游暗针叶林生态系统水管理具有极其重要的作用。通过研究表明 :长江上游暗针叶林生态系统的CWD总量是 10 1 74m3/hm2 ,它的组成体———倒木和站杆在不同演替阶段的容积和腐烂程度是明显不同的 ,随演替递进 ,程度加大 ,分布呈正态分布。CWD的腐朽级以处于第Ⅱ、Ⅲ和Ⅳ级为主 ,Ⅱ、Ⅲ、Ⅳ级的倒木、站杆和总的CWD蓄积量分别占倒木、站杆和粗木质残体总蓄积量的 86 12 % ,78 4 0 %和 79 6 5 % ,CWD的吸湿和脱湿过程是时间的指数函数。随着腐烂程度降低 ,CWD的持水能力也降低。Ⅰ级粗木质残体的天然和饱和的持水能力是 10 0 % ,Ⅴ级能分别达到它本身干———湿状态的 3 5～ 7 5倍 ,倒木的持水性大约是站杆的 10倍。暗针叶林生态系统的天然粗木质残体 ,能够截持 7 4 1mm的降雨量 ,饱和粗木质残体能够截持 9 91mm的降雨量
Coarse woody debris (CWD) plays an extremely important role in water management of dark coniferous forest ecosystems in the upper reaches of the Yangtze River. The results show that the total CWD of dark coniferous forest ecosystem in the upper reaches of the Yangtze River is 10 1 74m3 / hm2. The composition and volume of rotted wood and standing poles in different succession stages are obviously different. Successive succession, to a greater extent, the distribution was normal distribution. The rotten grades of CWD were dominated by Grade II, III and IV, and the accumulated volume of inverted wood, standing poles and total CWD in Grade II, III and IV accounted for 86 12 %, 78 4 0% and 79 6 5%. The moisture absorption and desorption of CWD is an exponential function of time. As the degree of decay is reduced, CWD’s water capacity is also reduced. Class Ⅰ crude woody residues of natural and saturated water holding capacity is 10%, Ⅴ level can reach its own dry --- wet state of 35 ~ 7 5 times, the water-holding capacity of the inverted wood is about 10 Times The natural coarse woody debris of the dark coniferous forest ecosystem is capable of intercepting 7 4 1mm of rainfall and saturated coarse woody debris capable of intercepting 991mm of rainfall