Relationships between wood density components and juvenile height growth and growth rhythm traits for Norway spruce provenances and families

Measurements of heights at ages 2, 4 and 7 years and of flushing, early sho ot elongation and lammas growth at age 7 years were made in nurseries and i n a short-term trial with seedlings from provenances and open pollinated fa milies of Picea abies. Fifteen of the provenances and 45 of the families we re planted in a long-term field trial. At age 29 years from seed, basic woo d density and its components: earlywood and latewood density and latewood p ercentage from increment cores were measured by X-ray analysis. The trees o f the northern provenances, which were the shortest ones, had the earliest growth start and the lowest proportion of trees with lammas growth, and had also the highest wood density and proportion of latewood. Moderate to stro ng negative relationships were found between the wood density traits and ea rly height growth and growth rhythm traits, suggesting that the latter ones could be good predictors of provenance differences in wood density. For th e families, much weaker and in most cases non-significant phenotypic correl ations were found between the two groups of traits. The genetic correlation coefficients were in most cases negative and had low absolute values. The possible causes of the differences in relationship patterns between provena nces and families are discussed.