Distributions and correlations of softwood fiber properties within age-classified pulps

The properties of softwood tracheids vary within a tree. This within-tree variation is a major source of variation between trees and stands. The effect of cambium age on the length, coarseness, and strength of Pinus silvestris and Picea abies tracheids is discussed. Distributions and correlations of Pinus silvestris tracheids within two age classes are introduced. Between pulps of different cambium age group, fiber length and coarseness are correlated; but within an age group, no correlation exists between fiber length and cross-sectional fiber dimensions. Between age groups, the major source of coarseness variation is cell-wall thickness; but within age groups, fiber perimeter also contributes to coarseness.