SOIL AND TREE WATER STATUS DYNAMICS IN A MIXED-CONIFER FOREST OF THE SOUTHERN SIERRA CRITICAL ZONE OBSERVATORY (SS CZO)

The results of a multi-year deployment of soil moisture sensors to study the hydrologic/ biotic interactions in a mixed-conifer forest at an elevation of ~2000m in the Southern Sierra Critical Zone Observatory (CZO) will be presented. To better understand root-soil water interactions in a multi-dimensional soil/vegetation system, a mature white fir (Abies concolor) and the surrounding root zone was continuously monitored (sap flow, canopy stem water potential, soil moisture, soil water potential and temperature), to characterize the hydraulics across the soil-root-tree-atmosphere continuum (SPAC). To better characterize processes in the subsurface, we excavated the root system of a nearby mature white fir, to quantify in situ root architecture using a Terrestrial LiDAR system . The data are used in a computer modeling study to test assumptions about tree root water uptake, to analyze soil water stress effects on tree water hydraulics and tree canopy transpiration.