PULPING AND PAPERMAKING PROPERTIES OF MANAGED 2ND-GROWTH SOFTWOODS

Differences between the wood, fiber, and pulp properties of juvenile a nd mature wood of second-growth Douglas-fir, jack pine, and lodgepole pine have been quantified. Juvenile wood is less dense and is drier if it is heartwood but wetter if it is sapwood. Juvenile wood gives lowe r kraft pulp yields, but these pulps have finer fibers than those from mature wood, and give sheets that are denser, smoother, more extensib le, and stronger in tensile. In mechanical pulping, juvenile wood requ ires more energy than does mature wood to refine to 100 mL CSF, but th e finer-fibered juvenile wood pulps have superior light-scattering abi lity. The implications of these differences are discussed with referen ce to transportation costs, kraft pulping, mechanical pulping, and the production of specialty pulps.