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



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. Copyright © 2008 John Wiley & Sons, Ltd.