Evapotranspiration from the understory of a tropical dry deciduous forest in Cambodia

作者：S. Iida, Takanori Shimizu, Koji Tamai, Naoki Kabeya, Akira Shimizu, Eriko Ito, Yasuhiro Ohnuki, Sophal Chann, Delphis F. Levia · 发表于：Agricultural and Forest Meteorology · 年份：2020 · DOI：10.1016/j.agrformet.2020.108170 · 被引用次数：29 · 研究领域：Plant Water Relations and Carbon Dynamics、Hydrology and Watershed Management Studies、Soil and Unsaturated Flow

The water balance of tropical dry deciduous forests is less well understood than some other forest ecosystems. To help close this knowledge gap, we separately measured the evapotranspiration from the whole ecosystem (ETW), transpiration (TR) and interception loss (IL) from overstory trees, and evapotranspiration from the understory vegetation (ETU) in a tropical dry deciduous forest in Cambodia. It was found that ETW was equivalent to 73.7% of rainfall (P) at the annual scale. In the dry season, ETW corresponded to 120.1% of P, which indicates the utilization of soil water replenished during the wet season. The sum of transpiration estimated by the thermal dissipation (TD) method with the original coefficient (TRG), IL, and ETU was smaller than ETW, except for the middle of the dry season, due to an underestimation of TRG. Although recently reported calibration coefficients can reasonably correct TRG, future calibrations of the TD method are highly recommended for the precise evaluation of single-tree-scale transpiration in tropical dry forests. The annual contribution of the understory vegetation to ETW (ETU/ETW) was 34.6%, leading to the conclusion that the understory vegetation cannot be ignored when trying to gain a comprehensive understanding of the hydrologic cycle in tropical dry forests. The seasonal variations in ETU/ETW were mainly controlled by the leaf area index (LAI) of overstory trees, resulting from the overall stability of ETW and decreasing trend of ETU with...