Transpiration from a Cryptomeria japonica plantation, part 2: responses of canopy conductance to meteorological factors

✍ Scribed by Hikaru Komatsu; Yihuei Kang; Tomonori Kume; Natsuko Yoshifuji; Norifumi Hotta

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 302 KB
• Volume: 20
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.6094

✦ Synopsis

Abstract

To our knowledge, there is no information on the canopy conductance of Cryptomeria japonica plantations, although such forests are very common in Japan. We examined the canopy conductance G~c~ of a C. japonica plantation based on 1‐year sap‐flow data using the simplified Penman–Monteith equation. After selecting data based on the criterion proposed in part 1 of this study (Komatsu et al., 2006. Hydrological Processes 20: this issue), we now examine G~c~ responses to meteorological factors.

G~c~ was expressed using functions of solar radiation S (W m^−2^), the vapour pressure deficit D (kPa), and air temperature T ( °C). The resulting functions were f~1~(S) = [(1000 + 30)S]/[1000(S + 30)], f~2~(D) = exp(−0·54__D__)/exp(−0·54), and f~3~(T) = {[(30 − 5) + 14](T − 5)}/{(30 − 5)[(T − 5) + 14]}, where f~1~(S), f~2~(D), and f~3~(T) are functions expressing the G~c~ responses to S, D, and T respectively. The functions were characterized by comparing general functions for coniferous forests, which showed that it was necessary to consider f~3~(T) to reproduce the 1‐year transpiration at the site, and that f~1~(S) and f~2~(D) determined here were not very different from the general functions.

This paper is the first to determine G~c~ responses to meteorological factors for a C. japonica plantation. When predicting transpiration from a C. japonica plantation using hydrological or ecological models, the functions determined here should be used instead of the default functions of the models. Copyright © 2006 John Wiley & Sons, Ltd.