An extraordinary forest has developed along the western slopes of the Coast Range where moisture is available in the greatest abundance. The most typical and beautiful expression of this coastwise forest is found in the western valleys and on the coastal plain of the Olympic Peninsula. It is the most luxuriant growth in any temperate climate and may properly be called a rain forest. This temperate-climate rain forest, however, is not like the rain forests of the hot, superhumid tropics. Here, there are tall conifers instead of broad-leaved trees; there are mosses and ferns on the ground instead of an understory of vines. The rain forest is principally distinguished by the presence of Sitka spruce. This tree grows only in a narrow belt along the coast from northern California to Alaska. The other trees of the rain-forest community have much wider distribution. The trees of this forest are among the largest in the world. Many of them have trunks that exceed 10 feet in diameter at 4½ feet above the ground, and are up to 300 feet tall. The largest known trees in the park for the most common species are: western redcedar, 21 feet 4 inches in diameter; Sitka spruce, 13 feet 4 inches; Douglas-fir, 14 feet 5 inches; western hemlock, 9 feet; and Pacific silver fir, 6 feet 10 inches. A visit to the rain forest offers a surprisingly enjoyable experience. Although it is possible to drive through some sections, this provides only a view of the trees. A forest is more than a stand of trees—it includes animal life, smaller plants, and micro-organisms, such as bacteria. All these serve the forest and in turn, their well-being depends upon the forest. They form the forest community. Splendid examples of rain forest may be seen in the Hoh, Queets, and Quinault Valleys, but the Hoh Valley is the most accessible. A paved road runs 19 miles up the Hoh from U.S. 101, ending 7 miles inside the park boundary where a National Park Service campground has been developed. The Hoh River Trail starts just beyond the nearby visitor center. It extends 18 miles to Glacier Meadow, close to Blue Glacier on Mount Olympus. Approximately 12 miles of it is in rain forest along the valley bottom. Only a small fraction of this distance need be traveled, however, to see the forest.