A simple stand model is developed to assess the influence of management activities in old growth Douglas-fir forests on atmospheric CO, levels. Two natural disturbance regimes (450- and 240-year stand replacement fire cycles) are compared with four management regimes (45, 6 5 , 90-year plantation rotations, and conversion to non-forest use). Conversion of old growth Douglas-fir stands to plantations may actually decrease atmospheric C 4 for the fist few decades, but then increase it. The short term and long term changes are negligible compared to the atmospheric C02 produced by burning fossil fuels. Using wood as a substitute product for other materials (brick, aluminum, and plastic) dramatically reduces CO, released to the atmosphere; however, where wood is used as a luxury product, large quantities of C02 are released to the atmosphere under harvest regimes.