The study area occupies about 31,285 km2, from Lake Erie to Georgian Bay and from the Carolinian Life Zone of southern Ontario north to the Precambrian (Canadian) Shield. It encompasses 14 upper-tier municipalities in central Ontario (Figure 1). The municipalities are, in alphabetical order:
- County of Dufferin
- Regional Municipality of Durham
- Regional Municipality of Halton
- City of Hamilton
- City of Kawartha Lakes
- Regional Municipality of Niagara
- County of Northumberland
- Regional Municipality of Peel
- County of Peterborough
- County of Simcoe
- City of Toronto
- Regional Municipality of Waterloo
- County of Wellington
- Regional Municipality of York
Three of these municipalities - the City of Hamilton (formerly the Regional Municipality of Hamilton-Wentworth), the City of Toronto (formerly Metropolitan Toronto), and the City of Kawartha Lakes (formerly the County of Victoria) - are single-tier municipalities, formed by the amalgamation of the lower-tier municipalities within each. The other 11 contain a total of 93 lower-tier municipalities (listed in the Appendix).
This study area is very similar to the Central Ontario Zone defined as part of the provincial Smart Growth initiative, which contains 17 upper-tier municipalities: the 14 listed above, as well as the Counties of Brant and Haldimand to the west and the County of Haliburton to the east. The study area covers 31,285 km2, an area slightly larger than the country of Belgium. According to the 2001 census, the population of the area is over 7.3 million people, which represents 64% of Ontario's population and over 24% of the population of Canada.
The area includes a variety of physiographic regions and life zones, including a significant portion of the Niagara Escarpment, the entire length of the Oak Ridges Moraine, extensive till plains, limestone plains, and open rock barrens. The forest types range from deciduous forests in the south, dominated by species with Carolinian affinities, to the mixed forests of the Great Lakes Region (Rowe 1972).