陕北黄土丘陵区油松林枯枝落叶层蓄积量及其动态变化

LITTER AMOUNT AND ITS DYNAMIC CHANGE OF PINUS TABULAEFORMIS PLANTATION IN LOESS HILLY REGION OF NORTHERN SHANXI

枯枝落叶层作为土壤覆盖层(A层),对防止雨滴的直接击溅,降低水流速度,抑制土壤蒸发,促进降水入渗,控制水土流失,均有重要的作用,是继林冠之后森林水文效应的第二个活动层。研究并查明枯枝落叶层的蓄积量及其动态变化,将为确切评价林分的水文生态功能,合理经营水源涵养林和水土保持林提供科学依据;同时,对研究生态系统的物质循环,也有重要意义。

The hydrological function of litter on woodland is closely connected withits amount. It is determined that the existing amount of litter in plantation ofPinus tabulaeformis at the age of 27-29 is 17.95t/ha; the annual litterfall am-ounts to 3.24t/ha. The changes of grand total litterfall (Y) with time (t)conform to functional equation: Y=-203.10+773.65t-113.60t^2+6.32t^3; andthe annual litter decomposition adds up to 3.23t/ha, its decomposition processchanges with seasons, more fast in rainly season and more slowly in winter.Thus at the present age and construction state, the litterfall and its decompo-sition of Pinus tabulaeformis are in balance, and the total amount of litter isrelatively constant.