Out-of-Roundness in Douglas-fir Stems

Abstract

Out-of-roundness (stem circumference not circular) of Douglas-fir stems was measured on cross sections of 806 trees felled and bucked according to current merchantability standards. Out-of-roundness (OOR) at stump height was greater than that in upper stem positions. Orientation of longest diameter (OLD) on gentle slopes showed significant, but slight, tendencies toward north and south directions and direction of slope. No such significant, or even apparent, tendencies were found on moderate or steep slopes. Because OLD was random in most circumstances, large-scale cruises using optical dendrometry for upper-stem measurements should be biased very little by OOR. The bias in volume estimates of individual trees, however, can be appreciable. Forest Sci. 21:365-370.