Routing stemflow water through the soil via preferential flow: a dual-labelling approach with artificial tracers

Abstract. Stemflow and its belowground funnelling along roots macropores may play an important role in the soil moisture redistribution forest environments. In this study, a stemflow experiment on Pinus sylvestris L. (Scots pine) used artificial tracers to view quantify preferential flow after infiltration into soil. A total of 41 L water labelled with enriched deuterium brilliant blue FCF were applied at rate 7 h−1 stem pine tree, which corresponds caused by about 50 mm rainfall. Time domain reflectometry (TDR) probes installed around tree trunk measure high-resolution volumetric content. 1 d discharge, pits dug different cardinal directions varying distances from tree. Photographs taken for imaging analysis metrics. Soil samples profiles analyse dye concentrations isotopic compositions. We found that infiltrated through annulus-shaped area base. observed heterogenous spatiotemporal response occurrence shallow perched tables trunk. Dye staining demonstrated primarily surface coarse macropores. The coverage was less extensive close increased depth proximity Lateral also observed, mainly layers. Our analyses demonstrate prevalence flow. Deuterium significantly correlated. tracer decreased increasing distance trunk, indicating dilution mixing residual water. Macropores, (living or decayed) produced complex network regulating results suggest affects distribution, thus likely groundwater recharge runoff. study provides insights hydrological processes are regulated improves our understanding forest–water interactions.