Pukaskwa represents the Central Boreal Uplands natural region within Canada’s National Parks System Plan. The Central Boreal Uplands, one of thirty-nine terrestrial regions in Canada’s National Parks System Plan, extends from northern Saskatchewan to western Québec – a massive expanse of boreal forest within the Canadian Shield. Pukaskwa is the only park in the national system representing this natural region.

The park’s location at the southern edge of the boreal forest results in the presence of both northern and southern tree species: white birch, trembling aspen, balsam poplar, black and white spruce, jack pine and white pine. The mixed forest cover is complemented by rare or unique flora, notably arctic-alpine plant species that cling to exposed bedrock, an endangered plant species known as the Pitcher’s thistle that occupies coastal dunes, and other rarities such as Franklin’s ladyslipper, northern twayblade, and mountain huckleberry – a shrub found nowhere else in Ontario.