Les caractéristiques papetières du bois attaqué par la tordeuse des bourgeons de l'épinette

Chemithermomechanical pulp was manufactured from a supply of budworm-killed balsam fir wood in a pilot plant at the Université du Québec. The physical properties of these pulps were evaluated according to the standard methods of the Canadian Pulp and Paper Association and compared with those of a corresponding sample of experimental pulp prepared from a supply of sound balsam fir wood under the same experimental conditions. It was found that the trees killed 3 years before they were cut produced significant reductions in tear strength (50%), breaking length (25%), burst (24%), and in its brightness (4.5%). The decreases were accompanied by a corresponding increase in the opacity of the sheet (5%) and a significant decrease in energy consumption (15%), the latter representing an important reduction in the electric energy cost of refining. Since in practice budworm-killed wood is always used in some blends with sound wood, the reductions in tear and tensile properties will be directly proportional to the proportions of each type of wood. Thus, in a 50/50 blend of chips made up of sound wood and budworm-killed wood, the burst strength is reduced only by 12%, but at the same time the decrease in the electric bill is also cut in half. Thus, if the budworm-killed forest is harvested not later than 3 years after the trees have been killed, the utilization of this wood in the pulp and paper industry is more promising than we were led to believe in the past.