The top layer of a temperate rain forest is known as the emergent layer. It is characterized by a fairly continuous tree canopy that receives most of the sunlight. The next level down is the understory. In this area of the rain forest, smaller trees and plants grow next to each another. The understory receives the remaining sunlight that manages to find its way through the canopy. The lowest level of the temperate rain forest is the forest floor. The forest floor is mainly devoid of direct sunlight. Small animals and insects live on the forest floor beneath the protection of dead needles, leaves and twigs that have fallen from the upper layers.
The tree and plant ecology of a temperate rain forest's emergent layer is relatively simple. The four trees that grow the tallest and dominate the canopy are the Douglas fir, the Sitka spruce, the Western red cedar and the Western hemlock. When full grown, these coniferous giants are between 130 and 280 feet tall. The understory of temperate rain forest environments is filled with shade-tolerant dogwoods and vine maples. Thimbleberry and huckleberry shrubs also thrive in the understory. The ground level of the temperate rain forest features mosses, grasses, lichens and fungi.
Animals that live in temperate rain forest environments usually live on or near the ground, where food and shelter are most readily available. Insects, rodents and birds are all abundant underneath the rain forest canopy. Beetles, slugs and spiders burrow in ground mosses, and woodpeckers, grouse and other rare bird species dominate the air. The largest animals found in the temperate rain forest are bears and deer.
Timber logging is a major threat to the remaining temperate rain forests of the world. Because the trees that make up the emergent layer of the rain forest are exceedingly tall, they tend to have tremendous value in the logging industry. Logging can also result in soil erosion. Rainstorm runoff oftentimes carries eroded soil in the form of silt toward oceans and lakes. The influx of large silt quantities, and the pollutants they carry, can have devastating effects on coastal marine life.
