Incidence of compression wood and stem eccentricity in lodgepole pine of North America

Abstract

Trees 76 mm d.b.h. had higher stem-average percentage of compression wood than those 152 mm or 228 mm d.b.h. Latifolia had less compression wood (5.5 percent) than murrayana (7.7 percent). In both varieties, stem sections from 45° through 50° latitude were proportionally more free of compression wood than sections from other latitudes. Transverse stem sections typically displayed a main body of compression wood opposite an eccentrically located pith. Percentage of compression wood tended to be higher in stems that were out of round and close to ground level, and if pith was eccentric, specific gravity high, and moisture content low. Cross sections averaged most elliptical in trees from 57.5° and 60° latitude. Both varieties were most nearly circular in cross section near midheight. Pith eccentricity averaged 6.7 mm and was least in intermediate latitudes (45° through 52.5°