Effects on Kraft and Mechanical Pulping and Pulp Quality when Utilizing Mountain Pine Beetle-Killed (MPB) Wood: An Overview

摘要

Increased salvage harvesting of lodgepole pine due to the current mountain pine beetle infestation in British Columbia's interior forests is changing the fibre supply for B.C.'s pulp mills. Green pine has been replaced by beetle-killed lodgepole pine of red and, increasingly, grey stage of attack, and the species balance of spruce:pine:fir (SPF) pulps has shifted from the traditional 30/65/5 ratio to a ratio of 80 to 90% pine. This study summarizes work that evaluated the impact of these changes on pulp quality. The influence of time-since-death and increasing pine ratio in SPF mixtures was evaluated through pilot plant kraft and mechanical pulping experiments using wood samples of different stages of attack and from different areas within the province. The use of red and grey stage wood does not impact kraft pulp quality, but for TMP, brightness and also sheet structural properties are affected. The increasing pine content in SPF mixtures has only a small influence, and the extent of possible changes varies with wood origin. Therefore red and grey stage beetle-killed wood can be used to produce kraft pulp with little concern, but for TMP, some concerns exist. Also, process-related impacts of using beetle-killed wood are not discussed in this paper.