This project aims at a more accurate determination of sap flow in trees and a better understanding of water transport dynamics. Sap flow measurements are used worldwide to estimate the water use in tree dominated ecosystems or to understand the ecosystem response to climate change (drought, heat waves, …). Accurate sap flow measurements are also important for a correct determination of stem respiration (linked to internal CO2 transport in tree stems) or to better understand special phenomena such as hydraulic redistribution. In this project two main sap flow methods are key: the Heat Ratio Method and the Heat Field Deformation method.