Budeanu, M., Şofletea, N.* and Petritan, I. C. 2014. Among-population Variation in Quality Traits in Two Romanian Provenance Trials with Picea abies L. Baltic Forestry 20(1): 37-47.

The descendants of 33 Norway spruce seed stands were evaluated at 30 years after plantation time, in two field trials established in different environmental conditions: outside of the natural range (ONR), at low altitude (Câmpina trial), and in natural distribution area (INR - Gurghiu trial), in Romania. Evaluations have been made concerning the most important growth, stem and branches characteristics: diameter at breast height (DBH), pruning height, pruning height ratio, trees slenderness coefficient, crown diameter, crown slenderness index, branches diameter and branches finesse. Highly significant differences (p < 0.001) were found among populations in both trials for most of the analysed traits (except DBH). Significant differences between Carpathian branches were recorded for most of the analysed traits, with a higher level in Câmpina comparative trial, suggesting different reactions of populations to the more adverse site conditions existing in the ONR trial. For all of the analysed traits, the populations showed superior results from a forestry point of view in the trial located in ecological optimum of Norway spruce (Gurghiu). Outside the natural range (Câmpina trial), populations present high values for slenderness trees, crown diameter and branches thickness, which increases the Norway spruce vulnerability to disruptive action of the abiotic factors such as wind and snow. Joint selection of Norway spruce populations for quantitative and quality traits is contraindicated. The two-stage selection strategy is applicable in this situation. Pruning height had the highest QST estimates.

Key words: comparative trials, correlations, DBH, seed stands, stem and crown traits.