用平均木法测定杉木林树干茎流的初步尝试

在广西田林老山林区同一杉木成熟林样地(800m~2)内,选用1株平均木和14株加权平均木的方法,分别对树干茎流进行了比较测定研究。结果表明:(1)用1株平均木测定法,具有简便易行、节省人力、财力的特点;与14株加权平均木测定法相比较,平均测定精度达到98.2％。(2)杉木成熟林开始产生树干茎流的时间比降雨开始的时间推迟8～50min,树干茎流终止的时间比降雨终止的时间延续47～140mim;一次树干茎流过程的总持续时间比降雨过程的总持续时间延续24～65min。(3)树干茎流位与降雨量呈直线相关;树干茎流开始产生的时间与茎流产生前时段的降雨强度呈对数函数相关;树干茎流的终止时间与降雨终止前20min时段的降雨强度呈幂函数相关。一次树干茎流过程的总持续时间与降雨过程的总持续时间呈直线相关。

INITIAL TRY TO DETERMINE THE CHINESE FIR FOREST STEMFLOW BY USING A MEAN SAMPLE-TREE METHOD

In this paper, the determination of the steamflow by using a mean sampletree method was compared with the method of fourteen weighted mean trees in different diameter steps in one sample land of the mature forest. The main results are: (1) A mean sample-tree method exists some advantages that doing it easily, reducing labour power and cost. The mean precision attains 98.2% that compare to the fourteen weighted mean sample-tree method. (2)The time that Chinese fir mature forest stemflow begins is 8 to 50 min later than the rainfall began. The stemflow stopped 47 to 140 min later than the rainfall ended. The stemflow lasted for 24 to 65 min more than the precipitation course. (3) It is a linear correlation exhibited between stemflow and rainfall capacity. A logarithmic function correlation occurred between the initial time of stemflow and the intensity of rainfall that prior to the stemflow begins. It is a power function correlation between the ending times of stemflow and intensity of rainfall in 20 min before the rain ends. It is a linear correlation between the total continued times of stemflow and that of rainfall.