Gap dynamics in Balsam Fir, Abies balsamea - Yellow Birch, Betula alleghaniensis, forests of Québec

Abstract

To determine if gap dynamics can play an important role in the natural regeneration process of Balsam Fir (Abies balsamea)-Yellow Birch (Betula alleghaniensis) forests and to determine the effects of gap characteristics on regenerating woody species, we sampled 119 gaps from 64 forest stands in La Mauricie National Park. Gaps averaged 184.5 m2 in size. The mean gap age was 7.8 years. Gaps were usually created by broken or uprooted trees and only rarely resulted from Spruce Budworm (Choristoneura fumiferana) outbreaks. We found 25 species that regenerated in the gaps or under the forest cover. When considering all species, significantly more stems/ha were in gaps than under the forest cover. Gap characteristics generally did not influence regenerating woody species. We present a comprehensive model of gap dynamics in Balsam Fir-Yellow Birch forests, starting from a dense canopy, continuing with the creation and colonization of gaps, and ending to the closure of the canopy. Gap dynamics play an important role in the natural regeneration process of Balsam FirYellow Birch forests.