Succession après épidémie de la tordeuse des bourgeons de lépinette (Choristoneura fumiferana) dans des sapinières boréales pluviales de seconde venue

Following spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks, Baskervilleʹs model (G.L. Baskerville. 1975. Spruce budworm: super silviculturalist. For. Chron. 51: 138-140), referred to as the cyclic model, is generally accepted as one of the best established regeneration models in wet boreal fir stands typical of northeastern America. According to that model, old virgin fir stands killed by the insect are replaced by other fir stands. In this study, we wanted to check if the cyclic model would work with wet boreal fir stands originating from harvest and having reached the felling age (50-60 years old) observed in Quebec. The study set up after the last budworm outbreak (1974-1987) shows that, although coniferous regeneration is bundant, the seedling bank is obviously immature: young and small seedlings, empty microsites. In most cases, the regeneration is codominated or dominated by deciduous species, which may bring about the development of a deciduous stand. Thus, the cyclic model does not seem suited to describe dynamics of second-growth boreal fir stands when it is kept in a premature state (<50-60 years old). These stands may not be as resilient as virgin ones, which are characterized by ecological rotations longer than 90 years.