粗木质残体(CWD)的水文生态功能——当前森林水文研究中被忽视的重要环节

目前对森林生态系统粗木质残体的研究主要着眼于数量动态、分布格局、分解速率以及生物多样性保护的作用上，而对江河上游森林生态系统中粗木质残体的水文调蓄、缓洪滞淤等功能至今还未能引起足够的重视。CWD作为森林生态系统的重要部分，茯水文生态功能的发挥主要是通过影响降水在林内的再分配以及林内微环境来实现的。森林CWD水文功能的发挥要同时受到外界环境和其本身持水性能的影响。CWD腐朽级别愈高，自然相对含水量愈高，而且愈容易吸水达到饱和。在长江上游亚高山暗针叶林生态系统中，自然状态下CWD可以蓄持约7.41mm的降水，若使CWD全部达到饱和则可以蓄持降水达9.91mm，这意味着自然状态下的CWD的有效持水量可达到2.50mm，无疑对于长江上游森林生态系统的蓄水调水、滞洪防蚀功能是一大贡献。

A Slighting Tache in Field of Forest Hydrology Research

Recently, most of researches on CWD focus on its quantity dynamics, distribution pattern, decomposing rate and its role in biodiversity protection.But there are some issues to be discussed further especially on its hydrological effects and role in soil and water conservation of forest ecosystem of upper reach of river.As a important part of forest ecosystem, CWD play its hydrological functions by influencing the redistribution of through precipitation and micro-environment in forest and inversely influenced by outside environment and its water-absorption capability.The higher decay degree of CWD is, the higher CWD's water-absorption capability.In sub-alpine dark coniferous ecosystem of upper reaches of Yangtze River, CWD can hold about 7.41mm precipitation under natural condition while 9.91mm under saturated condition, which is a great contribution to the hydrological function of whole forest ecosystem.