Temperate Rainforests

Temperate rainforests are dense rainforests that occur in the regions of high rainfall in the temperate zone. The  north temperate zone extends from the Tropic of Cancer (at about 23.5 degrees north latitude) to the Arctic Circle (at approximately 66.5 degrees north latitude). The South Temperate Zone extends from the Tropic of Capricorn (at approximately 23.5 degrees south latitude) to the Antarctic Circle (at approximately 66.5 degrees south latitude).  The regions in these latitudes, with annual precipitation over 1400 mm and mean annual temperature between 4 and 12 °C. (39 and 54 °F) are called Temperate Rain Forests.  The adjacent graphics shows the distribution of the Temperate Rainforests throughout the world.

Well-known temperate rainforests are found along the Pacific Northwest coast of North America, southern Chile, New Zealand, southern Australia, and the Black Sea coast of Turkey.

Climate

Temperate rainforests experience abundant precipitation averaging over 140 inches (350 cm) per year, mostly falling as rainfall. Summers are mild and winters are cool but rarely freezing. The ample rainfall and moderate temperatures create ideal conditions for dense evergreen forests to flourish. Fog is very common and contributes significantly to the hydration of plants.

Flora and Tree Species

The flora is characterized by towering evergreen conifers like redwoods, spruces, firs, and hemlocks, some reaching heights over 300 feet. Other trees include alders, maples, birch, magnolias, beech, laurels, and myrtles. A distinguishing feature is the lush, multi-layered understory with an abundance of ferns, mosses, lichens, and fungi. Epiphytes thrive in the humid climate and draped branches.

Coast Redwood Example

The coast redwoods in California and Oregon provide a prime example of temperate rainforests. Some coast redwood trees are over 2,000 years old and reach heights over 350 feet, making them the tallest trees on Earth. Redwood forests grow in a narrow strip along the Pacific coast where ample rainfall, frequent fog, and mild temperatures enable them to thrive. These magnificent giants once covered much of coastal California but have now been reduced to 5% of their original range.

Fauna

Temperate rainforests support an array of animal life. Mammals include black bears, foxes, wolves, cougars, lynxes, deer, racoons, and insectivores. Avian fauna ranges from eagles, owls and woodpeckers to smaller passerines. Reptiles, amphibians and abundant invertebrates also inhabit these forests. Most animals require large territories due to the dense vegetation and thrive where old growth forest remains intact.

Soil and Nutrient Cycling

Despite high annual rainfall, soils in temperate rainforests tend to be thin and nutrient poor. However, the closed nutrient cycling efficiently conserves and reuses nutrients. Decaying plant matter rapidly decompose on the damp forest floor, supplying vital nutrients like nitrogen and phosphorous. Mycorrhizal fungi form symbiotic associations with plant roots, enhancing their nutrient and water absorption.