What is the Carolinian forest in Canada?

The Carolinian forest is the southernmost ecoregion of Canada, covering about 21,500 square kilometres of extreme southwestern Ontario between Lakes Erie and Huron. The Canadian Carolinian forest is the northernmost reach of the eastern deciduous forest that extends south through the United States to the Carolinas (after which the ecoregion is named). The Canadian portion is small (less than one per cent of Canada's land area) but supports more rare and endangered species than any other comparable area in Canada.

The Carolinian forest is dominated by deciduous trees, including sugar maple, beech, white oak, red oak, black walnut, basswood, white elm, sycamore, butternut, and tulip tree. Several tree species reach their northern range limit in the Canadian Carolinian, including the tulip tree (Liriodendron tulipifera), the pawpaw (Asimina triloba, Canada's only species of the tropical custard-apple family), the Kentucky coffeetree, the eastern redbud, the cucumber tree, the dwarf hackberry, and the blue ash. The understorey includes the rare prickly ash, spicebush, witch hazel, and many spring wildflowers.

The Carolinian region supports about 25 per cent of Canada's species at risk despite covering less than one per cent of the land area. Notable rare species include the eastern fox snake, Blanding's turtle, the spotted turtle, the small-mouthed salamander, the Massasauga rattlesnake, the king rail, the prothonotary warbler, the Acadian flycatcher, the cerulean warbler, the Henslow's sparrow, the bobolink, and the eastern meadow-lark. The American chestnut, once the dominant tree species, was nearly eradicated by chestnut blight (a fungal pathogen accidentally introduced from Asia in 1904); restoration efforts continue.

The Canadian Carolinian zone has been heavily transformed by agriculture and urban development. About 90 per cent of the original forest has been cleared, with the remaining forest fragmented and largely confined to private woodlots, provincial parks (Long Point, Rondeau, Wheatley, Pinery), national parks (Point Pelee, the smallest Canadian national park at 15 square kilometres), and Carolinian Canada Coalition partner properties. Federal-provincial-private partnerships including the Carolinian Canada Coalition, Long Point World Biosphere Reserve (designated 1986), and the Niagara Escarpment Plan support remaining habitat protection. Climate change is allowing southern species to expand further north, but habitat fragmentation limits species response.