Residual effects of site preparation on growth and surface soil properties of Pinus taeda L. plantations

Residual effects, after 5 years, of four site preparation treatments: (1) cut and leave; (2) cut, leave and burn; (3) chop and burn; (4) shear, pile, burn and disk; originally applied in regenerating Pinus taeda L. plantations on three soils in eastern Texas; were evaluated by determining soil bulk density, organic matter, total nitrogen and extractable P, K, Mg, Ca and foliar P, K, Ca and Mg concentrations. By the fifth growing season, surface soil (0–8 cm) properties did not vary significantly except for N and Ca concentrations which were lowest for soils on the shear, pile, burn and disk treatments. Increased N and Ca concentrations for the shear, pile, burn and disk treatment below the 0–8 cm depth indicated the lower surface concentrations were a residual effect of disking. Foliar nutrient concentrations did not differ significantly except for foliar N concentrations which were lower for trees on the shear, pile, burn and disk plots.Residual treatment effects on stand development were evaluated by measuring fifth year stand density, stem diameter at breast height (1.4 m) and total height. Although the parameters were not significantly different, stands on the shear, pile, burn and disk treatment tended to have more stems of larger size than the other treatments.