人们知道,森林有保持水土、涵养水源、抗旱防涝、减轻洪水危害等功能。但这些功能表现的量如何?大概很少有人能作出确切回答。本文提供一些国外资料数据,对我们研究森林在生态方面的作用也许是有裨益的。首先,森林皆伐后,降暴雨时最大流量是森林皆伐前的1.2～2.5倍,或者更多些,随之而来的洪 People know that forests have the functions of conserving water and soil, conserving water sources, fighting drought and preventing waterlogging, and reducing flood hazards. But what about the performance of these functions? There are probably few who can make an exact answer. This article provides some data on foreign sources and may be helpful for us to study the ecological role of forests. First of all, the maximum flow after heavy rain is 1.2 to 2.5 times that of the forest before clear-cut, or more after the clear-cutting of the forest, and the consequent flood