In 1994 eighty four permanent research plots were established in two twelve year-old loblolly pine (Pinus taeda) plantations in East Texas. Plots differed in relation to: soil-site type, density of trees per acre, fertilization treatments, and competing vegetation control. Three levels of thinning treatments reduced the basal areas to 36,60, and 84 square feet of basal area (approximately 100,200, and 300 stems, respectively) per acre. All residual trees were pruned to a height of 25 feet. Plots were re-measured in 1995, 1996, and 1998. Significant differences in diameter and height growth rates were detected in 1996 and 1998. Average diameter growth rates from 1995 to 1998 ranged from 0.64 to 0.31 inches per year depending on density class and treatment type