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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...

In a study of specific gravity of second-growth ponderosa pine, there was visible evidence of resin in a part of the specific gravity specimens. Each specimen contained 10 annual growth rings in cross sections taken at 4 heights in the merchantable length of the trees. Since the presence of resin introduced an uncertain amount of error in the specific gravity values, it seemed advisable to extract the resin not only from the visibly resin-soaked specimens but also from all other specimens used. In this way, the general distribution of resin in the trees was found, and an approximate...

Observation and measurement of fibril angles in increment cores or similar small samples from living pine trees was facilitated by the use of fluorescence microscopy. Although some autofluorescence was present, brighter images could be obtained by staining the specimens with a 0.1% aqueous solution of a fluorochrome (Calcozine flavine TG extra concentrated, Calcozine red 6G extra, rhodamine 6G, rhodamine 6GD extra, or a succession of flavine and rhodamine). Staining for 2-5 min followed by a 5-10 sec washing in distilled water and drying 15 min at 190-195°C prepared radially split surf...

An American wood. Description of the distribution, growth, habit, wood, and wood properties of the species. Includes bibliographical references.

Replaced by FPL Research note 0138. https://www.fpl.fs.usda.gov/documnts/fplrn/fplrn138.pdf