(French title: Croissance juvenile comparee de deux generations successives de semis d'epinette noire issus de graines apres feu en foret boreale, Quebec) The objective of this study was to compare juvenile (0-12 years) height growth pattern of dominant mature trees from two virgin black spruce (Picea mariana) forests in Canada established during the 19th century (1870) to that of young dominant black spruce seedlings newly regenerated following a 1983 fire on the same sites. The pattern was reconstructed by measuring the distance between terminal bud scars on young seedlings, and by precise counting of growth rings by cross-dating from the collar, which was identified by anatomical features, for mature trees. New seedlings growth was significantly higher than that of mature trees. Seedlings were almost twice as high as mature trees after 12 years of juvenile growth. Assuming that mature trees were dominant during their juvenile growth phase, we put forward the hypothesis that juvenile height growth of mature trees would have been affected by the combined action of spruce budworm (Choristoneura fumiferana) and colder climatic conditions than those presently observed. Also, young seedlings juvenile height growth may have been favored by nitrogen soil enrichment along with more favourable climatic conditions.