Grekin, M. and Verkasalo, E. 2010. Variations in Basic Density, Shrinkage and Shrinkage Anisotropy of Scots Pine Wood from Mature Mineral Soil Stands in Finland and Sweden.  Baltic Forestry 16 (1): 113-125.

Variations in basic density, radial and tangential shrinkage, and shrinkage anisotropy of wood in mature Scots pine trees growing on mineral soil stands were studied based on empirical materials from five geographical regions in Finland and Sweden. Cambium age explained better the pith-to-bark variation in basic density, as well as in tangential and radial shrinkage, than the distance from the pith. The model for radial density variation was evaluated on a cross-sectional scale; it explained approximately 50% of the density variation of the cross-sections. Based on the mixed model analysis with repeated measurements structure, approximately 52% of the variation in basic density on a cross-sectional scale was explained by the geographical origin and height position within a tree. By adding variables describing the trees and stands more precisely, approximately 64% of the total variation within trees and between trees, stands, and regions could be explained. In both cases, within-tree and between-tree random variation was statistically significant. The geographical origin affected significantly the variability in the studied properties; especially the within-tree variations decreased from the south to the north. On the other hand, the average level of radial and tangential shrinkage, as well as basic density, was the lowest in the north.

Key words: Pinus sylvestris, Scots pine, wood quality, basic density, shrinkage, linear mixed model, repeated measures