Difference between the transpiration rates of Moso bamboo (Phyllostachys pubescens) and Japanese cedar (Cryptomeria japonica) forests in a subtropical climate in Taiwan

Abstract

AbstractBamboo forests have been expanding rapidly in Asian countries for the past 50 years. Whether natural or artificial, this expansion involves the replacement of other vegetation types by bamboo, which could impact the local water cycle. Previous studies in Japan have reported that bamboo forests have higher transpiration than coniferous forests under temperate climates, but it is unknown whether this finding applies to subtropical climates. Thus, we examined whether a Moso bamboo (Phyllostachys pubescens) forest exhibits higher transpiration in a subtropical climate. We used the sap‐flux method to estimate the stand transpiration (E) of Moso bamboo and Japanese cedar (Cryptomeria japonica) forests in Taiwan. As was observed in the Japanese studies, annual E for bamboo (478 mm) was higher than that for cedar (122 mm), although we found a difference in the seasonality of E between the Taiwanese and Japanese sites. Canopy conductance (Gc) for bamboo was higher than that for cedar in Taiwan, which was reported previously for Japan. Gc for bamboo in Taiwan was comparable to that in Japan, despite a difference in the leaf area index (LAI). Gc for cedar in Taiwan was lower than that in Japan. This difference in Gc between Taiwan and Japan corresponded to differences in the sapwood area and LAI. These findings suggest a significant change in E and, therefore, the terrestrial water and carbon cycle, regardless of different climates, when Japanese cedar forests are replaced by Moso bamboo forests.