Consequences of faster growth for wood density in northern red oak (Quercus rubra Liebl.)

The objective of this study was to establish whether the relationships between wood density, growth rate and ring number from the pith were equivalent in the contrasting conditions of a natural forest and an intensively managed plantation of northern red oak (Quercus rubra Liebl.). The radial X-ray densitometry profiles of 14 natural forest trees and 18 plantation trees growing in the southwest of Québec, Canada, were studied in detail using a linear mixed-effects modelling approach. In the natural stand, the effect of faster growth on overall ring density changed from a slightly negative relationship at a ring number 5 to a strongly positive effect at ring 40. In the plantation trees, the overall ring density remained almost constant along the range of observed ring widths. For the range of ring numbers common to both stand types (i.e. rings 1-15) the relationship was almost equivalent. Overall, our results suggest that because trees are harvested at a target diameter, silvicultural interventions specifically designed to improve radial growth rate in northern red oak will not be detrimental to overall wood density.