KRAFT PULPING OF 2ND-GROWTH LODGEPOLE PINE

The yield and quality of 36 unbleached kraft pulps from 12 second-grow th lodgepole pine trees at four sites in British Columbia and Alberta have been determined. Tree samples were separated into butt juvenile w ood, butt mature wood, and top wood components for kraft pulping, pulp property, and handsheet evaluation. Relative to mature wood, juvenile wood samples provided bleachable-grade pulps with lower yield and sli ghtly decreased alkali consumption, but with similar H factors. Kraft pulp fibers from juvenile wood and top wood samples were finer and sho rter than their mature wood counterparts and gave denser sheets that w ere smoother and less porous. Tensile and burst indexes and stress-str ain factors were higher, too, so these finer-fibered pulps would be mo re preferable for many paper grades such as lightweight coated.