Eastern Canada’s Temperate Rainforest

Temperate  and boreal rainforests grow discontinuously in the wettest and least fire susceptible parts of the Atlantic coast of Nova Scotia north to southern Labrador (43°─52° S) and on the Long Range mountains of the Avalon Peninsula of Newfoundland and the Laurentian and Appalachian highlands of eastern Quebec. This latter east-west expanse includes the Chic-Choc Mountains of the Gaspé Peninsula, the Kedgwick and Miramichi highlands of New Brunswick, and the Cape Breton Highlands of Nova Scotia. Similar forests also occur as “mountaintop islands” in the spruce-fir zone in the Appalachians Mountains of the United States as far south as the Great Smoky Mountains.

Mount Albert in the Chic-Choc range in the Gaspésie National Park in the Gaspé Peninsula of eastern Quebec.
Courtesy Fralambert [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]

Climate. These forests are impacted by the prevailing westerlies moving eastward across the North American continent. Frontal precipitation dominates and northeast tracking systems bring the greatest amounts of moisture to the north shore of the Bay of Fundy and the Atlantic slope of Nova Scotia and southern Newfoundland. The climate is classified as perhumid: precipitation exceeds evapotranspiration throughout the year. Annual totals vary from about 56 inches on the coast to about 40 inches inland. Additional moisture derives from sea fog. Southern and eastern Newfoundland have one of the foggiest sea-level climates in world; offshore the cold arctic waters of the Labrador Current converge with warm Gulf Stream water over the Grand Banks.

Predominantly continental airflow means wide seasonal temperature ranges, unusual in coastal rainforests. Long  winters and cool summers (Koeppen humid continental, Dfb, and subarctic, Dfc climates) are the norm. While the Atlantic waters and the Bay of Fundy remain ice-free in winter, the Gulf of St. Lawrence freezes over. Snow and snow melt are significant factors in the annual water budget.

Soils. This region was covered by great ice sheets during the Pleistocene so soil development is recent. Young, nutrient-poor soils derived from glacial till underlie most of the area. Poorly drained areas host peatlands.

Vegetation. In the northernmost parts of this rainforest region bordering the Atlantic and Gulf of St. Lawrence, boreal communities of conifers are dominated by balsam fir (Abies balsamea) and black spruce (Picea mariana). Mature firs may stand 15 ft. tall. White spruce (P. glauca) and heartleaf birch (Betula cordifolia) also grow here. A high diversity and biomass of lichens growing on both live and dead trees characterized old growth stands .In coastal areas, old man’s beard (Usnea spp.), a gray-green fruticose lichen, provides winter food for white-tail deer and nesting materials in summer for warblers. Old firs near the coast may host a rare and endangered cyanolichen, boreal felt lichen (Erioderma pedicellatum).  Epiphytic mosses are less diverse and common, but the ground layer is dominated by mosses and liverworts, including lanky moss (Rhytidiadelphus loreus), one of the feather mosses.  The main disturbance factors are insect irruptions, fungal diseases, and wind; fire is insignificant.

Boreal pelt lichen
Courtesy Ian Goudie [CC BY-SA 3.0 (https://creativecommons.org/ licenses/by-sa/3.0)]


The boreal rainforest transitions into a temperate rainforest known in Canada as the Acadian Forest type. This is a mixed conifer-deciduous broadleaf forest dominated by red spruce (P. rubens). Mixed in are balsam fir, yellow birch (B. alleghanensis). heartleaf birch, red maple (Acer rubrum), and mountain ash (Sorbus americana). The herb layer contains wood sorrel (Oxalis montana), whorled wood aster (Oclemena acuminata), and mountain woodfern (Dryopteris campyloptera). In the oldest, wettest stands thick carpets of leafy liverworts (e.g., the greater whipwort, Bazzania tulobata) compose the ground layer. Similar vegetation occurs on the higher elevations of the northern Appalachians.

Canada Warbler (Cardellina canadensis)
Courtesy William H. Majoros [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]

Animal life. Neotropical migrants such as Rose- breasted Grosbeak, Hermit Thrush, Canada Warbler, and Northern Parula (warbler) nest in these rainforests. Mammals occurring here include moose, whitetail deer, snowshoe hare, northern flying squirrel, mink, ermine, otter, and wolf.

Eastern Canada’s boreal and temperate rainforests are undergoing rapid ecological changes related to global warming of the climate. Warmer temperatures increase evapotranspiration rates, creating a drying environment. This in turn often means increased frequency of wildfire and insect outbreaks. It also increases decomposition rates and increased release of carbon dioxide from old growth forest and peatlands.


Banner photo: Cape Breton Highlands National Park, Nova Scotia. Courtesy of Tango7174 [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
Main source: Stephen R. Claydon, Robert P.Cameron, and John W. McCarthy. 2011. “Perhumid boreal and hemiboreal forests of eastern Canada.” In Dominick A. DellaSala, editor. Temperate and Boreal Rainforests of the World: Ecology and Conservation. Island Press.

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