Biomes: Coniferous Forest (1989)

[Music] [Music] [Music] A biome is a community of living things. The vegetation that develops in a certain climate region and the animal life that has become adapted to it. Of all the major forest biomes on Earth, the community most dominated by the smallest number of species is the coniferous forest. Coniferous forests grow on high mountain sides and on the level marshlands called the taiga. Even in winter, the leaves of these trees are green. Most of these evergreens are spruces, but the pine fur and hemlock are also part of the coniferous forest. trees that produce their seeds in cones. The coniferous forest forms a belt around the top of North America, Scandinavia, and Siberia. It requires a frostfree but cool growing season of from 2 to 5 months. The coniferous forest biome lies south of the Arctic tundra. Where the two biomes meet, there is often a visible tree line. The caniferous forest grows on land that was shaped by glaciers. During the last ice age, which finally ended about 10,000 years ago, glaciers advanced over the land. As they moved forward, they scraped off the top soil, gouged out hollows in the ground, and squeezed the coniferous forest into a narrow band at their southern edge. When the glaciers retreated, they left behind a rocky terrain. In this terrain, a few plants began to get a foothold. Among the first were lychans, which can survive in very difficult conditions. As the conditions for survival became more favorable, deciduous shrubs appeared and finally the conifers recolonized the land and became dominant. Conifers are well adapted for life here where snows are heavier than on the tundra. The conifers spirel-like shape and their flexible drooping branches help these trees shed heavy snows. In winter, when freezing limits the water available to tree roots, adaptations that prevent water loss ensure the conifer survival. The large tree is an unusual conifer. It sheds its needles during the winter and regrows them in the spring. The loss of needles reduces water loss. But most conifers are evergreens. They keep their needles throughout the year. Their thin needles expose little surface area and have waxy coverings which further help to reduce water loss. Because of the uniformity of the vegetation in the coniferous forest, there are fewer habitats here than in other forest biomes and consequently a smaller variety of animal life. In winter, the forest is quiet and still. There is little wind. The forest provides shelter for the few animals that stay active during the winter. The moose is the largest member of the deer family and so common to the conifer forest that the biome is sometimes called a spruce moose biome. In winter, the moose feed on woody plants, but depend mainly on body fat stored up during the summer and fall. This is a North American forest, but Scandinavia and Siberia have many of the same animals. The snowshoe hair develops furry pads on its hind feet that help support it in deep snow. Like the moose, snowshoe hairs are able to feed on twigs and dormant leaf buds. Migrating caribou spend the winter in the coniferous forest. The trees offer shelter from the bitter winter winds. In winter, ice locks up the water the trees of the forest depend on. But spring is approaching. Pintailed ducks arrive, beginning a massive migration of water fowl that will nest here along the waterways of the coniferous forest. Slowly, the ice gives way to water. There's more food available for the snowshoe hair. When the snow disappears, its changing color will protect it from predators like the grizzly bears emerging from their period of winter inactivity. During the winter, some females have given birth. Their cubs begin to explore the changing landscape. As the weather warms, melting snow and ice feed the vast network of streams that water the forest. [Music] Willows and other deciduous trees that grow along the waterways put forth their catkins that precede the growth of leaves. Frogs are among the few amphibians in the coniferous forest. After spending the winter buried deep in the mud of the pond, they emerge and mate. Only a few of the tadpoles that hatch from these eggs will ever become adult frogs. In some places where deciduous trees are mixed with conifers, the forest is less dense and sunlight can reach the ground. Only here can flowering plants grow that are the main source of food for animals in the forest. Aspen leaves, for instance, are the main food for the caterpillar of the aspen toxic moth. Unlike the broad leaves of deciduous trees, the needle-like leaves of conifers are tough and indigestible. Few animals can eat them, although birds like the red pole make their nests amid them. The young conifers, which can only grow in forest clearings, are safe from the browsing moose. The moose will eat green leaves, twigs, roots, bark, almost any part of a flowering plant that it can, but it leaves the needles of the evergreens alone. In southern coniferous forests where more deciduous trees grow, ponds are home to beavers. They feed on the branches of deciduous trees and collect them for underwater winter storage. Moose enter ponds to forage for underwater plants. This vegetation provides the bulk of their food in summer. Fungi function as decomposers here as they do in other biomes. As they break down the conifer needles that fall to the forest floor, they help to create the thin acid soil. They also provide food for red squirrels. Red squirrels carry the mushrooms to the tops of trees where they dry in the sun before the squirrels bury them. As autumn approaches, the growing season ends. Leaves of the deciduous trees begin to change color among the unchanging evergreens. [Music] There is very little fruit in the coniferous forest, but some flowering plants do produce berries at the end of the growing season. Animals turn to new sources of food. Bears fatten themselves on great amounts of these berries. As winter approaches, the red squirrel eats conifer seeds, but not while the cones are on the trees. It harvests pine cones by the thousands, throwing them to the ground. Now the squirrel prepares to store the cones it harvested. The seeds inside will keep the squirrel wellfed throughout the coming winter. The seeds of conifers also provide food for some animals like the cross bill. The cross bill's beak is especially adapted for removing seeds from deep inside the cones. The pah, a relative of the rabbit, is also busy preparing for winter. It gathers grass to store in its underground burrow. It stays alert for predators like this hawk. Temperatures [Music] fall. Daylight hours grow shorter. The growing season ends and it is winter again. Silence returns to the evergreens of this biome, the coniferous forest. [Music]