Estimates of short-run lumber supply elasticity derived from a published econometric model developed with 1947-70 annual observations were approximately 1.5 for Douglas-fir, Southern pine, and "structural species." The short-run estimates correspond to a 1 year length-of-run under a ceteris paribus (all else constant) assumption. Two indexes of intermediate-run supply response were constructed. These correspond to a 1 year length-of-run where price induced shifts of the short-run supply function are included. Both indexes indicate that intermediate-run supply response is generally less elastic than short-run response, particularly in later years of the sample period. Differences in the increase of raw material prices and increase of industry production capacity between regions and lengths-of-run probably explain these results. Forest Sci. 21:13-22.