Oak trees are the dominant tree type at our study catchments in Blue Oak Ranch Reserve, however they are not uniformly spread across the landscape. Oak trees are only established on north facing slopes, while grasses are dominant the south facing slopes. Our reserach group has observed higher subsurface moisture on south facing slopes than north facing slopes, which we believe is due to oak trees on north facing slopes needing water all summer long, while grasses on south facing slopes are only active during spring. Importantly, these differneces in subsurface moisture may contribute to aspect-dependent (north vs south facing) differences in runoff generation, landslide susceptibility, and drought resilience.