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.

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A phytosociological analysis of the deciduous forest region of extreme southern Ontario is presented. One hundred and thirty-one stands were sampled quantitatively t o determine the composition of the tree and sapling strata. A series of environmental characteristics were also measured or were carefully observed where measurement was impractical. The composition of the tree layer was expressed in terms of a series of importance values determined from measures of frequency, density, and dominance or basal area, on a relative basis, with the iinportance values for all trees in a stand summing to 300. An analysis of the relationship of the quantitative characteristics between all stands indicated the futility of the distinct association or distinct c o m m~~n i t y approach to an understanding of forest ecological relationships in the region. An ordination of stands in relatioil to site moisture characteristics gave expression to the ecological tolerance of individual tree species and emphasized the continuous characteristics of forest patterns in the vegetational complex of the area.The forests of southern Ontario were related quantitatively to those of southern Wisconsin utilizing a n index of regional influence based on overall importance for all tree species, in an attempt to interpret regional patterns within the Deciduous Forest Formation of North America.

The Monteregian Hills are a series of eight mountains, intrusive in nature, which form a distinct petrographical province in the St. Lawrence Lowlands of Southern Quebec. Mont St. Hilaire, one of the larger members of the group, was bequeathed to McGill University as a natural area for scientific research in 1959 by the late Brigadier A. Hamilton Gault. During a survey of the natural resources of the mountain throughout the summer of 1959, botanical investigations of the flora and vegetation were conducted. The present report is the first in a series that will present the results of these studies. It is concerned with the general characteristics of the mountain and the known existing flora.

Abstract. Two extensive forest vegetation survey datasets are explored, using ordination and classification, for evidence of in situ regeneration by Pinus strobus (Eastern white pine) and P. resinosa (Red pine). Ordination of tree species contributions to total basal area in 320 upland northern hardwood‐ conifer stands produced distinct stand groups for P.banksiana, P. resinosa, P. strobus and mesic hardwoods in an ascending sequence along the first axis. Quercus rubra (red oak), Q. alba (white oak) and tolerant conifer groups formed segregates from the hardwood complex along the second axis. P. strobus mixes with all other forest types, but P. resinosa is restricted to its own group. Seedlings and trees of P. strobus are more abundant than saplings, which are restricted to the pine and oak forests. Therefore, seed production, dispersal and seedling establishment seem to be less of a barrier to in situ regeneration by P. strobus than subsequent survival and growth. Canonical correspondence analysis of 170 pine‐dominated stands from the Canadian Shield of Ontario, in which tree species variables are segmented into height‐class pseudo‐ species, yielded no linear relationship between environmental features or stand structure and seedling densities of P. strobus. However, total tree basal area appears to impose an upper limit to seedling density on the forest floor. Strong correlations emerged between pine seedling density and understorey vegetation. Stand classification of the understorey vegetation, using constrained indicator species analysis, yielded distinct high and low seedling groups. Low pine seedling density was associated with abundant broadleaved shrubs, herbs and seedlings as well as feathermosses and tolerant conifers. High seedling density could not be ascribed to the presence of seedbed taxa, such as Polytrichum, but is ascribed to the absence of competition and other forms of inhibition in the understorey vegetation and down through the canopy profile. In situ regeneration of P. strobus does, therefore, occur but conditions over the forest landscape are largely restrictive.