The periodic occurrence of fires since the end of the last glaciation (about 8000 BP) has been documented
from lake sediments The fire regime for the last 300 years has been reconstituted using dendroecological methods It is characterized by the presence of intensive crown fires covering extensive areas (Fig. 1). The fire cycle (time necessary to bum an entire area> has been estimated at 63 years for the period before 1870 and at over 99 years for the period since 1870. However, during this latter period, fire frequency appears tohave constantly diminished and no important fire has
occurred since 1944. Since the beginning of the 20th century, major spruce budwonn (Choristoneura fumjferana) outbreakshave been recorded for the periods 19 19-1929, 1930-1950 and 1970-1987 During the last outbreak, on average 53% of balsam fir (over 5 cm diameter at breast height) were killed , creating large canopy openings in fir-dominated stands.