Forest thinnings for integrated lumber and paper production

Integrated lumber and paper productions using forest thinning materials from U.S. national forests can significantly reduce the cost of prescriptive thinning operations. Many of the trees removed during forest thinnings are in small-diameter classes (diameter at breast height <6 in) with suppressed growth. These trees produce low lumber yield but can produce quality thermomechanical pulps (TMPs) owing to uniformity of wood density and tracheid wall structure and a high mature wood fraction. This was demonstrated in commercial trials conducted at a lumber mill and a newsprint mill in the U.S. Pacific Northwest. Whole log and residual chips from forest thinnings produced at the lumber mill were combined with chips from normal pulping operations to produce newsprint. In all TMP trials, no significant change was found in correlations between the pulp long fraction and the pulp Canadian Standard Freeness.