A. Because of its great latitudinal extent, Canada has a wide variety of climates. Ocean currents play an important role, with both the warm waters of the Gulf Stream in the Atlantic and the Alaska Current in the Pacific affecting climate. Westerly winds, blowing from the sea to the land, are the prevailing air currents in the Pacific and bring coastal British Columbia heavy precipitation and moderate winter and summer temperatures. Inland, the Great Lakes moderate the weather in both southern Ontario and Quebec. In the east the cold Labrador Current meets the Gulf Stream along the coast of Newfoundland and Labrador, cooling the air and causing frequent fog.

B. The northern two-thirds of the country has a climate similar to that of northern Scandinavia, with very cold winters and short, cool summers. The central southern area of the interior plains has a typical continental climate—very cold winters, hot summers, and relatively sparse precipitation. Southern Ontario and Quebec have a climate with hot, humid summers and cold, snowy winters, similar to that of some portions of the American Midwest. Except for the west coast, all of Canada has a winter season with average temperatures below freezing and with continuous snow cover.

C. Both landforms and climate affect the distribution of plants, animals, and soils. Ecologists recognize broad regions called ecosystems that are characterized by fairly stable

complexes of climate, soils, and plant and animal life. The boundaries of these regions are not usually sharp lines on the landscape but are broad transition areas. The discussion that follows concentrates on preagricultural, or natural, vegetation. In southern Canada only remnants of these ecosystems remain.

D. Canada has several large and distinct forest zones, which blend into a number of transitional zones. The northern coniferous, or boreal, forest (taiga) is the world’s second largest area of uninterrupted forest; only Russia has a greater expanse of boreal forest. The severe winter and short growing season limit the number of tree species. Among them the white and black spruce and white birch are common, and balsam (fir) and tamarack (larch) also have wide distribution. The boreal forest is an important source of pulpwood and also produces considerable lumber, but much of the northern area is too inaccessible for commercial lumbering.

E. Not given in any of the above paragraphs.