岷江上游主要森林群落枯落物量及其持水特性

在四川卧龙森林生态定位研究站，通过野外收集与室内浸泡法，研究岷江冷杉林、川滇高山栎林及灌竹林3种典型亚高山森林群落类型的枯落物量及其持水特性的动态变化，目的在于为岷江地区天然林保护与林分经营管理提供理论依据。结果表明：1）一年中，3种森林群落类型枯落物蓄积量在不同生长时期差异明显，变化范围为10.00-25.20t／hm^2，在生长初期（5月份）和生长盛期（7月份），其顺序为岷江冷杉林〉川滇高山栎林〉灌竹林，在生长末期（9月份），其顺序为川滇高山栎林〉岷江冷杉林〉灌竹林。2）3种森林群落类型不同时期枯落物最大持水量均表现出分解层〉半分解层〉未分解层；3种森林群落类型枯落物最大饱和持水能力均较强，表现为岷江冷杉林〉川滇高山栎林〉灌竹林。3）3种森林群落类型枯落物持水量、吸水速率与浸水时间之间分别呈对数和幂函数关系，浸水前期的枯落物吸水速度变化最快，在0-5min达最大值，随时间推移逐渐降低，24h后吸水基本停止。

Litter amount and its water-holding properties of the main types of forest communities in the upper reaches of Mingjiang River

In order to qualify the eco-hydrological effects of the subalpine forest,the dynamic changes of three types of typical subalpine forest communities such as Quercus aquifolioide forest,Shrub-bamboo forest and Abies faxonian forest was investigated.The main results showed: 1) The litter accumulation of three types of forests varied from 10.00 t/hm2 to 25.20 t/hm2,the descending order is Abies faxoniana forest,Quercus aquifolioides and shrub-bamboo forest as both in May and July,and Quercus aquifolioides,Abies faxoniana forest and shrub-bamboo forest in September.The annual litter amount of Quercus aquifolioides forest is 391.5 kg/hm2 and 1 019.6 kg/hm2 more than Abies faxoniana forest and shrub bamboo forest respectively.2) The descending order of saturated water-holding capacity of litter is Abies faxoniana forest,Quercus aquifolioides and shrub-bamboo forest.3) The regression relationship between water-holding capacity,water-absorption velocity of litter and immerse time is logarithmic and exponential,respectively.The maxium velocity occurred during the first 5 immersing minutes,then decreased gradually,and fell to zero after 24 h.