Tree and oil palm water use : scaling spatial heterogeneity and temporal dynamics (Sumatra Indonesia) Transpiration is a central flux in the terrestrial water cycle and is considered an important ecosystem service for atmosphere and hydrosphere regulation. Transpiration is strongly affected by land cover and land use changes which are currently very pronounced in tropical regions. It is thus important to better understand transpiration in near natural and in human modified ecosystems. This includes aspects of spatio temporal variation and scaling. The main objectives of this study were (1) to test scaling approaches from individual plants to stand transpiration by using crown metrics (2) ...