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Transpiration from a Cryptomeria japonica plantation, part 2: responses of canopy conductance to meteorological factors
Author(s) -
Komatsu Hikaru,
Kang Yihuei,
Kume Tomonori,
Yoshifuji Natsuko,
Hotta Norifumi
Publication year - 2006
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.6094
Subject(s) - cryptomeria , japonica , canopy conductance , transpiration , vapour pressure deficit , canopy , stomatal conductance , environmental science , atmospheric sciences , hydrology (agriculture) , conductance , horticulture , ecology , mathematics , botany , biology , physics , geology , combinatorics , photosynthesis , geotechnical engineering
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.