Provenance Variation in Radial Increment and Wood Characteristics Revealed by 30 Years Old Norway Spruce Comparative Trials

The performance of 33 Norway spruce [Picea abies (L.) Karst.] seed sources from the Romanian Carpathians was evaluated with respect to growth and wood characteristics in comparative trials located at two different site conditions: Avrig- outside of the natural range of Norway spruce and Bret¸cu - within the natural range of this species. The radial increment (RI), latewood percentage (LWP) and conventional wood density (CWD) traits were evaluated at age 30 years after plantation. Phenotypic correlations between the evaluated traits, on the one hand, and between the same traits and the geographic gradients of the origin of seed sources, on the other hand, were calculated. Analysis of variance showed significant (p<0.01) differences between seed sources for RI, while for LWP and CWD, the differences were highly significant (p<0.001). These results suggest that selection at seed sources level could be possible. The test sites influence the LWP and CWD, while the RI is almost similar in both sites. For RI, the most valuable populations are situated in the Eastern and Western Romanian Carpathians. The highest LWP was registered for the Eastern Carpathian populations, while the lowest was recorded for the Western Carpathian populations. The Southern Carpathian populations, characterized by a lower growth rate, had higher values for wood density.