— Mountain pine beetle activity was monitored in one set of 2.5 acre plots in the southern por- tion of the Black Hills National Forest over a 17-year period. Beetles attacked 77 percent of the trees in the uncut control, 48 percent of the trees in the growing stock level (GSL) 100/110, 53 percent of the trees in the GSL 80/90, and 9 percent of the trees in the GSL 60/70. The percentages of MPB-attacked trees in each 1 in diameter class were lowest in the GSL 60/70, intermediate in the GSL 80/90 and GSL 100/110, and highest in the uncut control. Live basal area was significantly reduced in the GSL 80/90, GSL 100/110, and control but not in the GSL 60/70. Partial cutting to reduce beetle-caused mortality may be ineffective for partially cut parcels of <10 acres if the partially cut stands are surrounded by unmanaged susceptible stands. To increase the effectiveness of partial cutting, stands should be managed on a landscape basis. A 100-ft-wide strip with stand density of ≤GSL 70 between unmanaged and managed stands may be sufficient to limit the spread of beetle-caused mortality from unmanaged stands to adjacent partially cut stands. The Rocky Mountain Research Station develops scientific information and technology to improve management, protection, and use of the forests and rangelands. Research is designed to meet the needs of the National Forest managers, Federal and State agencies, public and private organizations, academic institutions, industry, and individuals. Studies accelerate solutions to problems involving ecosystems, range, forests, water, recreation, fire, resource inventory, land reclamation, community sustainability, forest engineering technology, multiple use economics, wildlife and fish habitat, and forest insects and diseases. Studies are conducted cooperatively, and applications may be found worldwide.