| Sumario: | The main objective of the thesis 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, significant differences between provenances were only found for the
frequency of straight and leaning trees. 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.
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