Effects of Cambial Age and Stem Height on Wood Density and Growth of Jack Pine Grown in Boreal Stands

Jack pine specimens were examined for longitudinal and radial variations in selected wood quality parameters. Wood density and ring width of cross-sections were measured systematically from pith to bark along the merchantable stem using X-ray densitometry. Effects of cambial age and stem height were analyzed using a linear mixed model with two levels of nesting. A strong interaction between the two factors was found in corewood. Tree individual variation increased with cambial age for all studied wood properties and was larger in earlywood than in latewood. Radial patterns in the studied parameters closely approximated published ones in the lower stem but lessened considerably with increasing stem height. By contrast, longitudinal patterns reversed with cambial age in earlywood. High coordination was found between longitudinal patterns in corewood and radial patterns in the stem base, indicating a similar maturation pattern in the apical meristem and cambia. However, with increasing cambial age, this high coordination disappeared rapidly