Hillslope soil physical properties and ecohydrologic measurements in Watershed 10, H.J. Andrews Experimental Forest, Oregon, USA (2023-2024)

Soil pits were excavated in 2023 across contrasting hillslopes in Watershed 10 at the H.J. Andrews Experimental Forest (LTER), Oregon, USA, to investigate how differences in subsurface water-storage capacity influence plant-accessible water, hydraulic redistribution, and associated soil physical, chemical, and biological properties in a second-growth Douglas-fir (Pseudotsuga menziesii)–dominated forest (~500 m elevation). The watershed receives >2000 mm annual precipitation, primarily as winter rainfall. Soil pits were hand-dug to ~100 cm, and bulk soil was sampled by horizon for physical and chemical analyses; intact cores were collected for soil water retention measurements. Pit-face photographs were used to quantify rooting distributions with depth. Each pit was instrumented with zero-tension lysimeters at two depths for bulk soil-water chemistry and with in situ sensors measuring volumetric water content, temperature, and electrical conductivity (multiple depths), soil CO2 (two depths), and soil water potential (one depth).