REGENERATION FOLLOWING FIRE OF THE BLACK PINE (PICEA-MARIANA) AND THE JACK PINE (PINUS-BANKSIANA) IN THE BOREAL FOREST OF QUEBEC PROVINCE

Age structure analysis was performed in black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.) stands following fire (i) to determine if there is a time lag between black spruce and jack pine establishment and (ii) to compare the composition of the regeneration with regard to the original stand. The study was conducted in an area burnt in 1983, 100 km northwest of Lake Saint-Jean, Quebec. Five years after fire, the age structure of the regeneration shows an early establishment of jack pine and black spruce, with more than 95% of the seedlings established during the first three growing seasons after fire (excluding the year of fire). The age structures were similar in mature stands and in the regeneration for the jack pine while they differed for black spruce. Errors in age determination due to suppression of adult trees sampled or other causes could explain the difference in the establishment pattern of young and mature black spruces. Compared with the mature stand, the postfire regeneration had an increased proportion of jack pine. The study concludes that both species can regenerate shortly after fire, but in somewhat varying proportions.