[en] Concentrations of ²³⁸Pu and ²³⁹,²⁴⁰Pu were determined in bark, organic matter, and soil samples collected in the summer of 1975 from pine (Pinus taeda) and hardwood (Quercus falcata; Carya tormentosa) stands near a nuclear fuel reprocessing plant at the U.S. Energy Res. and Dev. Admin.'s Savannah River Plant near Aiken, S.C. The results indicated that tree crowns intercepted fallout Pu (Pu-bearing particles) and produced higher Pu concentrations in the organic matter and soil under tree crowns. Higher ²³⁹,²⁴⁰Pu concentrations were found under pines than under hardwoods. Plutonium concentrations in the O1 (litter, A₀₀) and O2 (organic matter, A₀) layers were higher than those in mineral soil, but most of the Pu was contained in the mineral soil. Higher contents of ²³⁹,²⁴⁰Pu were observed near the tree stems than in locations outside of the tree crowns. In pines these values were 163 and 80 nCi ²³⁹,²⁴⁰Pu/m₂, and in hardwoods, 122 and 80 nCi ²³⁹,²⁴⁰Pu/m₂, for the respective locations, from the litter to the 15-cm depth. The proportion of ²³⁸Pu contained in foliage, litter, and organic matter was greater than for ²³⁹,²⁴⁰Pu. However, the latter radionuclides had a greater proportion contained in the mineral soil. This observation is consistent with the more recent releases containing a higher percentage of ²³⁸Pu from reprocessing operation. Plutonium concentrations in the 5 to 15 cm depth indicated limited Pu mobility in soil, but ²³⁸,²⁴⁰Pu concentrations at this depth were higher near tree stems, suggesting greater mobility perhaps as a result of stem flow