Most human activities in the Mixedwood Plains Ecozone, both past and present, are associated with urbanization. Containing 52% of Canada's 1991 population, it is the most densely populated ecozone in the country. Of the nation's 25 largest cities, 13 fall within the ecozone. The largest -- Toronto, Montreal, Ottawa, and Quebec City -- are connected by extensive networks of expressways. Between 1966 and 1991, Toronto's population grew by 80%, and the Toronto metropolitan area now houses 14% of all Canadians, compared with 11.5% living in the Montreal area.

Even though 85% of residents live in urban areas, settlement patterns have changed from the traditional compact, centralized city to new suburbs spreading into surrounding countryside. Smaller cities are no exception. Kitchener-Waterloo, for example, grew by 57% between 1971 and 1991. Several outlying municipalities north and east of Montreal, such as St-Lazare and Blainville, also grew by over 40% from 1986 to 1991. Home to 11 million people in 1971, the entire ecozone supported 14 million just two decades later.

Intensive urban development in the Mixedwood Plains has led to severe environmental degradation. Relocation to the suburbs and urban fringe escalated dependency on private automobiles. Consequently, residents in the Windsor-Quebec City corridor now breathe some of the highest levels of air pollutants, including ground-level ozone and suspended particulates.

The Mixedwood Plains had an estimated Gross Domestic Product in 1991 of $325 billion, contributing 55% of Canada's total. The ecozone provides 34% of Canada's resource-based employment, and half of that number work in the agriculture and food industry. The ecozone's service industry, constituting a third of the labour force, is immensely important to national and international trade and commerce. Oil refineries, power-line corridors and industrial parks dotting vast tracts of the landscape are evidence of the ecozone's dominant service and manufacturing industries.

Fertile soils and a relatively mild climate have created excellent agricultural land in the Mixedwood Plains. In fact, the ecozone contains over 50% of Canada’s class 1 agricultural land, and 62% of the land with a capability of classes 1, 2, and 3. The Niagara Peninsula, famous for its fruit orchards and vineyards, is the warmest and most intensively cultivated part of the ecozone. Corn, soybeans, and specialty crops such as tobacco and vegetables are concentrated in southern regions enjoying 2 000 to 2 500 growing degree days. The cultivation of mixed grains also enhances hog, dairy, and beef livestock production throughout the ecozone. Today, urban expansion is the primary reason for loss of prime agricultural land.

Tourism and recreation continue to strengthen the Mixedwood Plains' economy. The spectacular Niagara Falls, CN Tower in Toronto, and the historic cities of Montreal and Quebec are a few of the many popular tourist attractions. Numerous northern communities, once heavily dependent on logging and mining, have turned to tourism for additional sources of revenue. Cottage development along the Great Lakes and St. Lawrence shorelines has intensified as urban residents spend more of their leisure time beyond city limits. Marinas, resorts, and restaurants are now common sites in the countryside.