Tree xylem isotope analysis by mass and laser spectrometry
The use of xylem isotopes is an increasingly commonly used approach in eco-hydrological studies. Carrière et al.  used this dataset to better understand where trees uptakes water under drought condition on a Mediterranean karstic system. Despite this technique is widely used, analytical issues still discussed within user community. We have conducted a number of tests which are relevant to be shared to animate the debate. We show that mass and laser spectrometer analyzes give very similar results for 46 xylem water and 9 drainage water samples. The full dataset (219 samples) shows that the xylem water undergo a deuterium fractionation which make the deuterium data unusable in the current state.