Variation of Sap Flow Density of Larix principis-rupprechtii with Dominances And Its Impact on Stand Transpiration Estimation

• Published in: Forest research (Beijing) Vol. 28; no. 1; pp. 8 - 16
• Main Authors: LI, Zhen-hua, WANG, Yan-hui, YU, Peng-tao, WANG, Yan-bing, HAN, Xin-sheng, CAO, Gong-xiang
• Format: Journal Article
• Language: Chinese
• Published: 01.02.2015
• Subjects: Larix
• ISSN: 1001-1498

It is a basic approach to estimate the stand transpiration through computing the average of sap flow density (J[sub 3]) from a number of sample trees and then up-scaling. In order to understand the difference in J[sub 3] among trees of different size or degree of dominance, and further improve the accuracy of the up-scaling approach, a field experiment was conducted in a Larix principis-rupprechtii stand located at the semi-arid region of Liupan Mountains. Then the differences in J[sub 3] among individual trees under three kinds of soil water conditions were analyzed with the data at mid-growing season when the tree leaf area reached to the maximum and remained relatively stable. The value calculated by the average of J5 for the five sample trees was 16% lower than that calculated by the widely used approach. Therefore it is pro- posed that the degree of dominance should be taken into account in the up-scaling approach for the stand's J[sub 3] or transpiration estimate in future.