Estimation of vertical profiles of leaf drying times after daytime rainfall within a Bornean tropical rainforest

摘要

South-east Asian Bornean tropical rainforests have large and complex canopy structures. To clarify how forest structure affects wet-canopy evaporation, it is necessary to consider wet-canopy evaporation processes within the forest canopy, such as vertical profiles of canopy drying time. In a previous study a method was proposed that utilizes sap flow measurements to estimate canopy drying time after rainfall {CDTobs) during daytime. In this present study, the method was applied to estimations of the vertical variations in CDTobs in 11 individual trees of various heights, ranging from 2.7 m to 53 m. The study derived vertical profiles and showed that the lengths of CDTobs in lower canopy trees were 2-4 h longer than those in the upper canopy trees. The new method for CDTobs profiles presented in this study, which is available for validation of multi-layer biosphere-atmospheric models, is a useful illustration for clarifying wet-canopy evaporation processes in tropical rainforests.