A research in Japan showed that the expansion of bamboos may impact on the local water cycle, as the annual transpiration (E) of Moso bamboo forest (MBF) was much higher than nearby coniferous forests in summer. To confirm this finding, we compared the E of MBF under different climate. We (1) estimated the annual E of a MBF (in the mountainous humid area of Xitou, Taiwan) using sap flow method, (2) compared the results with a cedar forest nearby, as well as a MBF and two cedar forests in Fukuoka, Japan, and (3) used a canopy conductance (Gc) model to define the impact of meteorological factors on E. Results showed that in any case, the annual E of bamboos was much higher than conifers. The similar Gc observed between bamboos of the two sites suggest that differences in E was mostly created by different meteorological conditions. Moreover lower temperature during winter in temperate areas may alter the correlation between E and VPD, resulting in that in areas like Xitou with less distinctive seasonal variations, the difference of annual E between bamboos and conifers was even higher than forests situated in temperate areas.

Keywords : Moso Bamboo, transpiration, canopy conductance.