Coniferous Forest

Coniferous Forest
In North America coniferous forests form a broad, continuous, continentwide belt stretching across Canada and Alaska, and south through the Rocky Mountains into Mexico. This biome continues across northern Eurasia, making it one of the largest plant formations on earth. It is dominated by evergreens—pine, fir, spruce, and cedar—which are adapted to withstand freezing and take full advantage of short summer growing seasons. Conical trees with their flexible branches shed snow easily. The northern area is the boreal (northern) forest, often called taiga (a Russianword, pronounced “tie-ga”). The taiga is dominated by white and black spruce, balsam, subalpine fir, larch, and birch. Mean annual precipitation is less than 100 cm (40 inches) and the average temperature ranges from +5° to −3° C (23° to 37° F). In the central region of North America, the taiga merges into lake forest, dominated by white pine, red pine, and eastern hemlock. However, most of this forest was destroyed by exploitive logging and was replaced by shrubby second growth, which still characterizes much of Michigan, Wisconsin, southern Ontario, and Minnesota today. The large southern evergreen forests occupy much of the southeastern United States. The last old growth coniferous forests of the Pacific northwest are rapidly falling to commercial logging. Mammals of the boreal and lake coniferous forests are deer, moose (Figure 39-7), elk, snowshoe hare, a variety of rodents, carnivores such as wolves, foxes, wolverines, lynxes, weasels, and martins, and the omnivorous bears. They are adapted physiologically or behaviorally for long, cold, snowy winters. Common birds are chickadees, nuthatches, warblers, and jays. One bird, the red crossbill, has a beak specialized for picking seeds from cones. Mosquitoes and flies are pests to both animals and humans in this biome. Southern coniferous forests lack many mammals found in the north, but they have more snakes, lizards, and amphibians.