Abstract Douglas-fir (Pseudotsuga menziesii var. glauca) ponderosa pine (Pinus ponderosa var. ponderosa), and western white pine (Pinus monticola) where chemically root pruned with cupric carbonate (CuCO3) during greenhouse production. The interior walls of Styroblock 4A® and Ray Leach® pine cell containers (each 66 cm³) were coated with latex paint containing CuCO3 at concentrations of 0, 30, 100, or 300 g/l. Seedlings were potted after one growing season, initiating a standard root growth potential test (Duryea 1984). The number and length of new roots more than 1 cm in length were measured. Seedling root systems increased in total root number and length, especially in the upper segments of the root plug, as a result of chemical root pruning. Seedling height and caliper were unaffected by the cupric carbonate treatments during the production phase, and a latex paint carrier did not decrease seedling growth. West. J. Appl. For. 4(1):15-17, January 1989.