Dynamics of the boreal forest south of James Bay

Abstract

Ordination models of approximate environmental and dynamic relationship between eight boreal tree species were constructed based upon principal components analysis and Kruskal's nonmetric multidimensional scaling. The assumptions inherent in these models are stated and discussed. The data consisted of 152 forest stands from the closed-crown boreal forest zone of Ontario and Quebec south of James Bay. Sequential forest succession, as demonstrated by similar techniques for a section of the Wisconsin evergreen–hardwood forest, is not common in the region of boreal forest studied. However, for those species in common between this and the Wisconsin study, similar dynamic pathways are indicated despite differences in sample size and field technique. Tree species developmental pathways, as indicated by 'succession vectors' on the ordination models are, for the most part, short and circular with the exception of Abies balsamea (balsam fir). This reflects the reestablishment of similar, relatively monospecific forest stands following catastrophic forest destruction by fire and (or) other agencies. Where catastrophe does not intervene, deciduous primary forest species may be succeeded by an understory of A. balsamea or by Picea mariana (black spruce). Equally, some forest stands of primary establishment may become decadent with little or no subsequent tree growth. These observations are discussed with respect to the general notion of forest succession.