Dynamics of the boreal forests of the Laurentian Highlands, Canada

Abstract

Analyses of species composition and tree increment cores from 145 stands in central Québec were used to determine the forest history and stand dynamics. Windspread fires, possibly synchronous, burned across central Québec in at least three periods of record (1661–1663, 1779–1791, 1869–1871). The average fire rotation (time interval between natural fires burning the equivalent of a large area) for spruce – feather moss forests was approximately 130 years, and 70 years in either deciduous or jack pine forests. The traditional succession concept of continual recruitment leading to an all-aged forest was not evident in these forests. About 70% of the overstory trees were established in the first 30 years after fire disturbance, with little recruitment after this time. These initial trees dominate the canopy for up to 250 years with mortality becoming prominent after 130 years. The short average time between disturbances precludes the probable degeneration into old shrub-filled stands typical of old age.