Transfer effects and variations in basic density and tracheid length of Pinus sylvestris L. populations

Basic density and tracheid length were assessed in 67 provenances from one or more of 18 provenance trials at the age of 30 years. From each provenance and trial 10 trees were sampled from a 1.25 metre spacing and I0 trees from a 2.0 metre spacing whenever possible. Assessments were made at growth rings five and ten respectively from the bark for basic density and at growth ring five from the bark for tracheid length. Provenance variation was significant for basic density and tracheid length in 50% of the trials. A narrow spacing increased basic density but tracheid length was not changed. Basic density was low in trees with large diameter or wide growth rings and in assessments made close to the pith. Tracheid length was short in short trees and assessments made close to the pith. Contour plots of basic density and tracheid length indicate that low values are obtained for northern latitudes and high altitudes. Tracheid length was also reduced at coastal sites. Transfer functions indicate in general that a southward and upward transfer increases basic density and fibre length. The study indicates that changes in forest management and forest tree breeding are needed in order to increase basic density and fibre length