Wood density and growth in clonally propagated aspen

摘要

Do fast-growing trees produce lower density wood? To determine the relationship between growth rate and wood density in plantation-grown aspen (Populus tremuloides Michx.), 199 trees in 20 clones were sampled from a 15-year-old clonal trial. This study found no evidence that fast-grown trees produce less dense wood. Phenotypic and genetic correlations between height, diameter, volume, and biomass were all high and significant. Wood density was not correlated with height or volume, but there were small and significant (p = 0.05) positive phenotypic correlations with stem diameter. Genetic correlations between breast-height wood density and all three growth measures (height, DBH, and volume) were not significantly different from zero. This suggests that selection for growth will not influence wood density and vice versa. This paper discusses some possible reasons for the contradictions in the literature about the relationship between growth rate and wood density in aspen. The anatomy of juvenile or core wood is different from that of mature wood, and the relationship between density and growth rate also differs. The changing relative proportion of juvenile core wood with tree size may explain many of the apparent contradictions.