Chemimechanical pulping of boles and branches of white spruce, white birch, and trembling aspen

Abstract

Very high yield bisulfite chemimechanical pulps were prepared from boles and branches of white spruce (Piceaglauca (Moench.) Voss.), white birch (Betulapapyrifera Marsh), and trembling aspen (Populustremuloides Michx.). In general, the branches produced 5 – 7% less pulp than the boles. The branch pulps showed weaker mechanical properties than the corresponding bole pulps. The mediocre performance in strength characteristics of the branch pulps may be attributable to the differences in dimension of fibers and vessel elements and the relative proportion of these cells in the wood.