A quarterly econometric model of Douglas-fir Region forest products markets was used to simulate the response of prices and output to alternative National Forest timber supply policies. The model explicitly treats behavior in public and private stumpage, log, lumber, and plywood markets. Under a simulated policy of increased annual sales offerings (using an historical simulation period), the initial response of prices at all market levels was small. Significant price reductions lagged supply shifts by more than one year. Over the full simulation period, average reductions in lumber and plywood prices were less than one-tenth of the reduction in bid price. Differential price responses arose in part from compensatory reductions in private harvest and from the insensitivity of lumber and plywood prices to price changes at lower market levels. Simulation results cast doubt on the effectiveness of National Forest supply policies aimed at controlling prices of secondary products in the Region. Forest Sci. 20:243-259.