HOLOCENE FOREST DYNAMICS WITH RESPECT TO SOUTHERN ONTARIO

The pattern of change in the Holocene forests of southern Ontario is o utlined and discussed in the light of external and internal forcing fa ctors. Forests are seen as non-linear, dynamic systems, that are, at a ny point in time, unique and changing. Major forcing factors during th e Holocene are believed to be (1) climate, controlling the floristic p ool from which forests developed; (2) soil development, which slowed t he invasion and increase of some mid- and late-Holocene forest dominan ts) and (3) internal forest dynamics, controlling the pattern of chang e and the development of vegetation. The system is heavily influenced by historical events, such as the mid-Holocene decline of hemlock. For est composition is likely to be similar, in the broadest terms, from o ne interglacial to another, but always to vary in detail. The interact ion of individuals, populations and environmental variables ensures th at, although deterministic, prediction of change will always be diffic ult.