Comment on hess-2020-671

Abstract

Mennekes et al. present an experimental study in which they apply in-situ water isotopic monitoring techniques to estimate water travel times through the soil-plant-atmosphere continuum in three species with contrasting wood anatomy. They compare water travel times derived from in-situ isotopic monitoring with those obtained with sap flow measurements. At the same time, they also compare the isotopic results from the in-situ monitoring system with those of more traditional (destructive) approaches. The in-situ monitoring of isotopic composition appeared to estimate travel times consistently as travel times were very similar as those estimated with sap flow sensors. On the other hand, the isotopic composition as measured with the three different techniques was highly divergent.