What is a Temperate Rainforest?
A temperate rainforest is a forest in a temperate climate with ample annual rainfall. These types of rainforests can include both coniferous trees (which do not shed their foliage) and deciduous trees (which lose their leaves on an annual basis).
Temperate rainforests serve as habitats for a wide array of plant and animal species. These include tall trees like Sitka spruce and western hemlock, plants, and shrubs like ferns along the forest floor, and animals ranging from bald eagles to black bears to mountain lions to multitudes of insects. Most of the world’s temperate rain forests are protected in parks. This limits logging within their bounds, permitting the existence of old-growth forests.
Climate change has resulted in habitat loss for many common trees, and even the largest temperate rainforests have seen their footprints reduced over time. The reduction of such forests is harmful to the environment, as they absorb tremendous amounts of carbon dioxide and harbor a wide variety of native species.
What Are the Characteristics of a Temperate Rainforest?
In order to qualify as a temperate rainforest, the forest must have annual precipitation of at least 55 inches (140 cm) and average annual temperatures ranging between 39 and 54 degrees Fahrenheit (4 to 12 degrees Celsius). Precipitation can come in the form of rainfall or, as is common in the temperate rainforests of the Pacific Northwest, fog.
The species of trees found in temperate rainforests vary by region, but they tend to include a variety of tall conifers and broadleaf trees, including western red cedar, western hemlock, Sitka spruce, coast redwoods, coast Douglas fir, and vine maple. Trees that fall in temperate coniferous forests can decay on the forest floor and become nurse logs, which anchor and feed new temperate rainforest plants and provide shelter for small mammals.
Where Are Temperate Rainforests Located?
Temperate rainforests can be found on all of Earth’s continents except Antarctica. The Northern Hemisphere harbors temperate rain forests in the United States, Canada, Japan, Taiwan, Iran, Great Britain, Ireland, and northern Spain. In the Southern Hemisphere, South American temperate rainforests exist in southern Chile; New Zealand has many temperate rainforests, and even notoriously dry Australia has small areas of temperate rainforest, such as Lamington National Park in Queensland.
The Pacific Coast of North America contains the longest strip of coastal temperate rainforests. It begins in northern California forests such as Redwood National Park, works its way through the coastal areas of Oregon and Washington—including the Hoh River Rainforest in Olympic National Park—into British Columbia through coastal forests like Great Bear Rainforest and Chilliwack River Provincial Park, and on into coastal Alaska, where ancient forests like the Tongass National Forest occupy temperate regions of the state.
Differences Between Temperate and Tropical Rainforests
The primary difference between temperate rainforests and tropical rainforests—such as those found in Hawaii, Brazil, Central America, and Southeast Asia—is location, and thus temperature. Temperate rainforests fall within latitudes of 40 to 60 degrees north and south, and their temperature remains mild year-round. Tropical rainforests exist much closer to the equator, falling between latitudes 23.5 degrees north and 23.5 degrees south. This means they are much warmer, which allows them to support different species of plants.