Birch wood quality of different genetic origin

The main objective of the research was to find out how the wood quality differed among Silver birch provenances. The study was conducted in family, provenance and tree species experiments in SW Sweden. External features like stem straightness, spike knots, double leader, diameter, tree height, leaning and other defects were measured and analyzed. Significant differences were found between birch families and provenances for a number of measured parameters. In the family experiment, significant differences between families were found for the parameters straight trees and diameter while no significant differences were found for others measured parameters like spike knots, forking, leaning and tree height. The local provenance Tönnersjöheden had the best overall quality and growth in the provenance experiment while Kulbäcksliden provenance (North Sweden) had a low overall quality. In the tree species experiment, Asarum was suggested a good quality provenance with an overall high quality performance and a low percentage of leaning trees while Visingsö was judged a bad quality provenance with a high percentage of crooked stems and a many leaning trees.