Relationship between specific gravity and percentage of summer wood in wide-ringed, second-growth Douglas-fir

Abstract

For the sample of wide-ringed Douglas-fir discussed in this report, the relationship between specific gravity and percentage of summer­wood is linear over a range of 16 to 60 percent summerwood content of the annual ring. The specific gravity of the summerwood and springwood portions of 96 dissected annual rings is also linearly re­lated to the percentage of summerwood in the annual rings, so that the specific gravity of both increases with an increasing percentage of summerwood. The zero and 100 percent summerwood intercepts of the regression of specific gravity on percentage of summerwood of whole annual rings do not give valid estimates of the average spe­cific gravity of springwood and summerwood .

Citation

Smith, D.M. 1955. Relationship between specific gravity and percentage of summer wood in wide-ringed, second-growth Douglas-fir. Report No. 2045. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 19 p.