Abstracts for the 5th International GAME Conf.

3-5 October 2001

Aichi Trade Center

Nagoya Japan

Comparison of seasonal trend in sap flow rate between deciduous and evergreen trees in northern Thailand

Natsuko YOSHIFUJI (1), Nobuaki TANAKA (1), Chatchai TANTASIRIN (3), Hideki TAKIZAWA (4), Masakazu SUZUKI (1), Nipon TANGTHAM (3)

In order to compare seasonal trend in transpiration from deciduous and evergreen forest under tropical monsoon climate, sap flow measurement has been conducted in the deciduous teak forest at the Mae-Moh plantation (1825f N, 9943f E) and in the hill evergreen forest at the Kog-Ma experimental watershed (1848f N, 9854f E), because sap flow rate can be a useful indicator of transpiration rate. Continuous observation of sap flow rate of a single trees in both sites have been carried out using the heat pulse method and the stem heat balance method together with micrometeorological observation as a part of a field experimental study of energy and water balance of GAME-T project. These two sites under tropical monsoon climate have a marked seasonality of precipitation. The dry season continues for 4 to 6 months including December to March, and it is characterized by declining soil moisture and high vapor pressure deficit. The notable difference in sap flow between these two sites appears in the dry season. In the deciduous teak forest, sap flow is quite active in the wet season, it gradually declines as leaves fall off a tree during the first half of the dry season, and no sap flow is observed during the leaf less period in the late dry season. In the hill evergreen forest, daily maximum value of sap flow rate keeps nearly equal or higher value in the late dry season compared to the wet season, even though the very dry soil moisture condition. The large difference in seasonal trend in energy and water cycle between deciduous and hill evergreen forest is expected because of the different behavior of sap flow during the dry season in each forest.

Submittal Information

Name : Date :
    Natsuko YOSHIFUJI
    31-May-01-16:19:19
Organization : Theme :
    School of Agriculture and Life Science, The University of Tokyo
    Theme 2
Address : Presentation :
    1-1-1 Yayoi, Bunkyo, Tokyo
    Only poster
Country : Abstract ID :
    Japan
    T2NY31May01161919
Phone : Fax :
    03-5841-5214
    03-5841-5464
E-mail :
    natsuko@gaia.fr.a.u-tokyo.ac.jp