Toronto was founded in 1793 as a reaction to the American Revolution. The existing capital of Upper Canada at the mouth of the Niagara River on the south side of Lake Ontario, was too close to the Americans for comfort, and it was decided to move it here, where there was a protected harbor, hardly any native people, and endless forest. It was designed a city in 1834 and enjoyed rapid growth because of its harbor, easy access to the north, rich farmland, and ability to attract immigrants. People took full advantage of abundant year-round water supplies to establish a thriving lakeshore colony. Access to the hinterland to the north was readily gained via a network of stream fed by springs that issued along the southern flank of the Oak Ridges Moraine.

Over time, early pioneers spread into this heavily forested region and began to clear large tracts of land for farming. Extensive clearance of forest cover and the denuding of watersheds began after 1840 and caused widespread devastation of the habitats of animals and indigenous people. Deforestation in the Toronto region peaked late in the nineteenth century, when the value of forests for lumber and firewood was overtaken by the forests’ non-timber value, also the effects of deforestation on regional climate and groundwater supplies, especially in the Oak Ridges Moraine, were recognized as a major problem worthy of federal and provincial attention, deforestation slowed gradually over the twentieth century. But since the time people changed forest into residential area or other uses, the character of land use changed and could never changed back like before.