Forest soil characteristics under varing tree species in East Texas: implications for sustained productivity

Abstract

The maintenance of long-term soil productivity is very important to forest managers for continued production of greater quantities of wood from a smaller land base in shorter periods of time. Nutrient cycling is a vital component of long-term soil productivity, and tree species may alter nutrient cycles within the same location and soil type through time. This study examined the influence of 33 years of sit occupancy by lobolly pine (Pinus taeda L.) and oak (Quercus spp.) plantations on forest floor mass and nitrogen (N) and phosphorus (P) concentrations, in StU C02 efflux, soil microbial biomass carbon (SMBC), in situ N mineralization and nitrification rates, and soil bases, pH, and organic carbon (SOC). Forest floor phytomass was greater in the pine treatment, while N and P concentrations were lower, resulting in similar total N and P content in the forest floor of the pine and oak stands. In situ C02 efflux was greater in the oak treatment, while SMBC was greater in the pine treatment. SMBC-to-SOC ratios were high for both treatments, whereas they were greater in the pine treatment which suggests a greater possible increase in SOM. N mineralization showed less seasonal variation than expected and was similar for both treatments.