INFLUENCE OF THE SPRUCE BUDWORM, CHORISTONEURA-FUMIFERANA (CLEM), ON REGENERATION OF FIR STANDS AFTER CLEARCUTTING

An analysis of over 100 balsam fir [Abies balsamea (L.) Mill.] stands has shown some effects of spruce budworm defoliation on regeneration a fter clearcutting. Even though softwood stocking was consistently high prior to harvesting operations, longer infestation periods or more se vere defoliation levels led to a decrease in the stocking of softwood stems above 50 cm height and to the establishment and development of h ardwood advance growth. Hardwoods were more often in a dominant positi on in the most severely damaged stands and the budworm effect was stil l persistent on the regeneration structure even 5 years after logging. Cutovers with less than 60% stocking were also more frequent in the m ost severely devastated fir stands. This situation seemed directly rel ated to the impact of the spruce budworm on balsam fir advance growth.