Differences in growth and wood density in clones and provenance hybrid clones of Norway spruce

Abstract

The growing forest bioeconomy calls for enhancing wood production in Finland. Accordingly, we studied phenotypic differences and correlations for growth and wood density traits in 25 Norway spruce (Picea abies (L.) Karst.) genotypes grown in a field trial established in the 1970s in southeastern Finland. We also studied the effect of the geographical origin of parent trees. The clones represented six southern Finnish and two southwestern Russian clones and three Finnish–Swiss, eight Finnish–German, three Finnish–Latvian, and three Finnish–Estonian hybrid clones. Some local Finnish clones (e.g., V43) and provenance hybrid clones (e.g., Finnish–German V449 and V381) clearly displayed higher stem volume than the average over all of the clones and relatively high overall wood density (and wood biomass yield). The increase in latitudinal transfer distance of parent trees compared with the latitude of the trial seemed to decrease the height, diameter at breast height, and stem volume, but the effect was not significant (p > 0.05). The overall wood density was affected significantly only by the latitude of the father parent trees (p < 0.05). Wood density traits showed clearly lower phenotypic variation compared with other traits. Contrary to our hypothesis, none of the studied hybrids showed superior properties compared with the local Finnish clones.