Densité et largeur des cernes des populations d'Épinettes blanches de la région forestière des Grands Lacs et du Saint-Laurent

Abstract

Twenty years after planting, X-ray densitometry and immersion were used to determine the relative density of wood from 28 white spruce populations of the Great Lakes – St. Lawrence forest region. The results showed the same pattern of radial variation in all populations. Wood density decreases for the first few years of growth, then stabilizes for a time, then increases slowly, but steadily. The relative density of wood from white spruce has a slight, negative correlation with the width of the annual growth rings, at either the individual or the population level. However, some populations and individuals do deviate from this trend. Though the populations showed some statistically significant differences in relative density, analysis of variance showed that 85 to 90% was attributable to differences among trees within the same population. This study confirmed the desirability of using relative density as the basis for making mass selections within fast-growing white spruce populations to genetically improve the genetic quality of wood.