Reply on RC1 [* Cross-Reference *]

We combined sap velocity measurements with isotopic measurements of soil, precipitation, stream water, groundwater, and xylem over 2019 and 2020 in the Luxembourgish site and 2021 in the Italian site. We found that in the Weierbach catchment, trees' response to environmental variables (i.e., vapour pressure deficit and relative extractable water in the soil) was similar among hillslope positions and between the two monitored years resulting from homogeneous growing conditions along the topographic sequence.

We also did not find any statistical difference in the isotopic composition of xylem water among positions suggesting that beech trees relied on similar water sources across the landscape. In the Lecciona catchment, we observed lower sap velocities and shorter growing season in trees growing in the upper portions of the hillslope, likely related to water redistribution and different soil moisture along the hillslope catena.

Xylem isotopic composition was significantly lighter at the footslope location throughout the growing season than in the upslope locations, suggesting location-specific water use. These results emphasize how differing hydrometeorological processes occurring at the hillslope scale can lead to contrasting tree performances. ***This entry has been automatically imported via OpenAlex by LIST harvest scripts. Please refer to doi.org/10.5194/hess-2023-225-ac1 for the original and latest version of the publication***