Tree and log characteristics, wood properties, and lumber yields both visually graded and machine-stress-rated (MSR), were determined for good-site 95 year-old Lodgepole pine (Pinus contorta Doug. var. latifolia Engelm.). A total of 220 trees were selected by diameter-at-breast height (d.b.h.) class in three samples representing end-of-rotation stand densities of 700, 1100 and 1900 stems/hectare
(s/ha).
Lumber recovery factor increased with increasing tree d.b.h. class, but due to greater stem taper, was lowest for comparative d.b.h. classes in the 700 s/ha stand density class. Yields of MSR and premium visually determined structural and appearance lumber grades increased as stand density increased. Wood basic relative density was inversely related to d.b.h. Lumber modulus-of-rupture (MOR) and modulus-of-elasticity (MOE) decreased as tree d.b.h. increased. Wide dimension lumber from large-diameter open-grown trees generally failed to meet in-grade specifications for MOR and MOE. Juvenile wood, as measured by 15- and 30- year-old proportions of tree stems, was only weakly related to MOR and MOE. Drying degrade was unrelated to proportions of juvenile wood. For Lodgepole pine grown on good sites, the optimal combination of lumber yield and grade will be achieved by targeting a medium (eg. 10001200 s/ha) final stand density.
Key words: Pinus contorta, lumber recovery factor, lumber strength, juvenile wood, wood density.
Correspondence: Gerald R. Middleton, Forintek Canada Corp., 2665 East Mall, Vancouver, British Columbia, Canada V6T 1W5
Telefax: +1-604-2225690
E-mail: gerry@van.forintek.ca