Olympic National Forest
The temperate rain forest in the valleys of the Quinault, Queets, and Hoh rivers are protected and contain some of the most
spectacular examples of undisturbed Sitka spruce/western hemlock forests in the lower 48 states. This ecosystem stretches along the Pacific Coast from Oregon to Alaska; other temperate rain forests are found in several isolated areas throughout the world. What defines a rain forest quite simply is rain--lots of it. Precipitation here ranges from 140 to 167 inches--12 to 14 feet--every year. The mountains to the east also protect the coastal areas from severe weather extremes. Seldom does the temperature drop below freezing in the rain forest and summertime highs rarely exceed 80 F.
The dominant species in the rain forest are Sitka spruce and western hemlock; some grow to tremendous size, reaching 300 feet in height and 23 feet in circumference. Douglas-fir, western redcedar, bigleaf maple, red alder, vine maple, and black cottonwood are also found throughout the forest. Nearly every bit of space is taken up with a living plant. Some plants even live on others. These are the epiphytes, plants that do not come into contact with the earth, but also are not parasites. They are partly responsible for giving the rain forest its "jungly" appearance.
Mosses, lichens, and ferns cover just about anything else. Oregon oxalis is also a common ground cover. But because of this dense ground cover it is hard for seedlings to get a start. Many seedlings germinate on fallen, decaying trees. As they grow they send their roots down the log to the ground. Eventually the log rots completely away and a row of young trees is left, up on stilt-like roots, all in a row. The thick and protective vegetation also provides excellent habitats for the animals of the rain forest. In turn, they contribute to the health of the forest by keeping the rampant vegetation under control by browsing.
For more information, go to http://www.fs.usda.gov/olympic/.