Small-diameter trees used for chemithermomechanical pulps.

During the course of restoring and maintaining forest ecosystem health and function in the western interior of the United States, many small-diameter stems are removed from densely stocked stands. In general, these materials are considered nonusable or underutilized . Information on the properties of these resources is needed to help managers understand when timber sales are a viable option to accomplish ecosystem management objectives. Pulp is a logical use for this small-diameter material. In this study, chemithermomechanical pulps (CTMP) were prepared and evaluated from lodgepole pine and mixed Douglas-fir/western larch sawmill residue chips; lodgepole pine, Douglasfir, and western larch submerchantable logs; and lodgepole pine, Douglas-fir, and western larch small trees. Douglasfir/western larch mixture and lodgepole pine sawmill residue chips obtained commercially were used as the control in making comparisons. CTMP prepared from Douglas-fir small trees, Douglas-fir submerchantable trees, and lodgepole pine small trees consumed the most electrical energy during pulp preparation had the best paper strength properties, and the poorest optical properties compared with the control. Lodgepole pine submerchantable logs consumed less electrical energy, had marginal strength properties. and poor optical properties. Western larch submerchantable logs and small trees had the lowest electrical energy consumption, poor strength properties, but some of the better optical properties. The pulp preparation procedures selected for western larch submerchantable logs and small trees were detrimental to the pulp and paper properties.