Wood quality of Pinus sylvestris progenies at various spacings

Abstract

Effects of genetic entry and spacing, and their interactions, on volume production, basic density, tracheid dimensions, and functional classification were evaluated for sawn timber in a combined progeny and spacing trial with Pinus sylvestris in southern Sweden. Five genetic entries, consisting of open-pollinated progenies from two plus trees and two minus trees and the local-provenance marker, were studied at three spacings (1.2, 2.0 and 3.0 m). The assessments were made 30 years after planting. Basic density increased from pith to bark and decreased from stump to 6.0 m height. Wood quality was generally low, as indicated by the visual grading of logs and central yields and by strength grading. Entry and spacing had significant effects on most properties. Generally, wood quality was highest for fast-growing entries at dense spacing. The local provenance was not inferior to the plus-tree progenies, but was superior to the minus-tree progenies. When effects of entry and spacing were eliminated, partial correlations between growth and quality traits were weak.