HOLOCENE FOREST DYNAMICS WITH RESPECT TO SOUTHERN ONTARIO

The pattern of change in the Holocene forests of southern Ontario is outlined and discussed in the light of external and internal forcing factors. Forests are seen as non-linear, dynamic systems, that are, at any point in time, unique and changing. Major forcing factors during the Holocene are believed to be (1) climate, controlling the floristic pool from which forests developed; (2) soil development, which slowed the invasion and increase of some mid- and late-Holocene forest dominants) and (3) internal forest dynamics, controlling the pattern of change and the development of vegetation. The system is heavily influenced by historical events, such as the mid-Holocene decline of hemlock. Forest composition is likely to be similar, in the broadest terms, from one interglacial to another, but always to vary in detail. The interaction of individuals, populations and environmental variables ensures that, although deterministic, prediction of change will always be difficult.