Differences in growth and wood property traits in cloned Norway spruce (Picea abies)

Abstract

Volume growth has typically been used as a selection trait of prime importance in forest tree breeding. Less attention has been given to the genetic or phenotypic relationships between the growth or yield and wood density traits. In the above context, we aimed to investigate the phenotypic relationships among different growth, yield, and wood density traits of 20 Norway spruce ( Picea abies (L.) Karst.) clones grown in southeastern Finland, in order to identify whether a high growth rate was associated with low wood density in any of the clones. Compared with growth or yield traits, the wood density traits showed lower phenotypic variations. The phenotypic correlations between growth, yield, and wood density traits were, on average, from moderate to high, suggesting that selection for one trait would simultaneously affect the other traits. Compared with volume production, selection based on stem mass could be more profitable if a clonal stand is managed for pulpwood rather than mechanical wood processing and vice versa; whereas selection for overall wood density alone would reduce both the stem volume and stem mass. However, by compromising the gain or loss in wood density and stem volume, clones with high stem volume and a relatively high wood density could be found.