High?resolution temporal dynamics of intra?storm isotopic composition of stemflow and throughfall in a Mediterranean Scots pine forest

Vegetation plays a significant role in the isotopic fractionation of rainwater during rainfall partitioning through canopy into throughfall and stemflow. Most studies focus on composition throughfall, whereas that stemflow has been studied much less frequently. Moreover, only three to date have investigated at intra-storm scale. Therefore, knowledge shift between throughfall/stemflow fine resolutions is sorely needed order better understand water input forest soils. In this study, intra-event rainfall, Scots pine under Mediterranean conditions were monitored (5-min time step) over 20-month period (May 2018 December 2019) samples each component collected sequentially by means automatic samplers for analysis (18O 2H). Results obtained 21 events show was usually more enriched than throughfall. Isotopic differences indicated depleted higher air temperature season enriched. The did not any direct relationship with either meteorological variables or amount effect. At scale, start event tended decrease towards end. Our results suggest evaporation led enrichment due residing longer vegetative surfaces However, most factors can occur same event. study will improve understanding physical processes control coniferous trees before reaching ground, as step improving isotope-based models forest-water interactions.