Just south of our transect on the western side of the Olympic Peninsula are unique rainforest communities unlike those found anywhere else in the world. Most of the rainforest communities around the world are restricted to warm, tropical areas, and they are typically dominated by evergreen trees that are flowering plants. Most of the trees in the temperate rainforests of the Olympic Peninsula are conifers. Like other rainforests, the temperate rainforests of the Olympic Peninsula are rarely disturbed by fires; their trees are evergreen rather than deciduous (that is, they do not lose all of their leaves at the same time each year); they have abundant epiphytes (plants that live on other plants); and they have a dense, shrubby understory. The temperate rainforest communities of the Olympic Peninsula are most well developed in the valleys of the Bogachiel, Hoh, Queets, and Quinault Rivers. They form best in the four rivers valleys because of their extremely high precipitation, mild winters, and cool summers.

The canopy of the temperate rainforest creates a cool, deeply shadowed world.	The Olympic temperate rainforest is a moist world of tall trees and dense shrubs in the understory.

The vegetation of the temperate rainforest is lush: even the surfaces of trees support other plants and lichens.

The temperate rainforest has the same major trees as described above in the coastal forest communities. The conifers in the rainforest communities can reach record size. The world's largest known western hemlock (Tsuga heterophylla), western red cedar (Thuja plicata), and Douglas fir (Pseudotsuga menziesii) are found in the Olympic rainforest. The sitka spruce (Picea sitchensis) are also enormous; indeed, they are the largest trees of the temperate rainforest and can be 8 feet in diameter and over 200 feet tall. Because of the size of these trees, the conifers of the Olympic Peninsula are particularly sought-after as lumber. There has been considerable debate about whether to preserve the old forests of huge trees because of their beauty, the uniqueness of the organisms they house, and their importance in maintaining environmental quality or to cut them because of their economic value as lumber.

Western red cedar	Douglas fir

In old forests of the Olympic temperate rainforest, the trees can be massive.	Much of the temperate rainforest of the Olympic Peninsula has been logged because the trees have great economic value. Clear cuts such as shown here destroy the entire forest during logging and create many environmental problems.