Granitic bedrock is the dominant parent material found in the mixed conifer zone of the Sierra Nevada Mountains of northeastern California. The bedrock often is highly weathered to depths of 4 m or more, and is capable of holding plant-available water. Pine tree roots exploit fractures in the weathered bedrock and extract water found therein. The impact of weathered granitic bedrock on forest productivity is relatively unknown. The goal of our research was to determine the effects of soil and weathered bedrock on ponderosa pine productivity. Several sites were selected in the Sequoia National Forest. The site index was determined based on analysis of individual trees, rather than on the entire soil site. The mean annual increment (MAI) of volume (cm³ year^-1) was calculated from field measurements. Soil depth was determined by augering four holes around each tree. The soil depth ranged from 19 - > 300 cm, while the site index ranged from 40-70 ft in height. The MAI ranged from 9,948-61,368 cm³ year^-1. The MAI increased as soil depth increased from 19-175 cm. Basal area was not affected by soil depth. The regressions of soil depth were not generally significant to site productivity measurements, indicating that other factors are more influential to ponderosa pine productivity. It is clear that soil thickness alone is not a major determinant of ponderosa pine productivity in this area. Since total plant-available water storage depends on the volume of both the soil and the weathered bedrock, the total regolith depth may influence tree productivity to a greater extent than does the soil depth alone. Ground penetrating radar (GPR) analyses are scheduled to supply the data on total regolith depth.