CHEMITHERMOMECHANICAL PULPING CHARACTERISTICS OF BUDWORM-KILLED TREES

Chemithermomechanical pulps (CTMP) were produced from balsam-fir trees [Abies balsamea (L.) Mill] that were harvested one and three years af ter they were killed by spruce budworm beetles. Laboratory tests revea led that the spruce budworm produced significant reductions in wood de nsity (30%), fiber length (19%), long fiber fraction (36%), brightness (4%), tensile strength (25%), and burst strength (24%), but most sign ificantly in the tear strength of paper (51%). However, these negative effects were accompanied by some positive results, e.g., a 15% decrea se in the energy of refining, a 73% reduction in pulp rejects, coupled with a 108% increase in the fine content of the pulp and by a 5% incr ease in the opacity of paper. In order to profit from the above advant ages and to prevent any further reduction in the quality of paper, the dead trees must be harvested within three years of their defoliation - the sooner, the better.