Chemistry and pulping feasibility of compression wood in black spruce

This research was conducted to study the organic and inorganic constituents and pulping behaviour of compression wood (CW), in comparison to normal wo od (NW) and opposite wood (OW). It was found that differences in the chemic al properties of OW and NW were not significant, except in alpha-cellulose and hemicellulose content; whereas both differed significantly from CW whic h contained more lignin and calcium and less alpha-cellulose. These chemica l characteristics of CW resulted in high residual lignin and poor pulp yiel ds, in comparison with normal and opposite woods, when different cooking ti mes and temperatures were applied. Bleachable grade pulp could be obtained from normal wood with H-factor 2300. Using CW, however, this was not practi cal even under severe cooking conditions.