About Coastal Temperate Rain Forests

World biome types in relation to precipitation and temperature

World biome types (and major climate types, in all capital letters) in relation to precipitation and temperature. Boundaries are approximate and are affected by soils, disturbance (e.g. fire, wind), and local typography. Temperate rain forest vegetation is found along a broad spectrum of climate types from cool/drier (4°C MAT/1,400mm MAP) to warm/wetter (17°C MAT/3,300mm MAP). North American coastal temperate rain forests occupy the cooler and moister portion of the range with the exception of redwood forests which can be relatively warm and dry. Redrawn from Whittaker, 1975.

Temperate rain forests have, since the mid-20th century, been recognized as a distinct biome type. Distinguished by high precipitation, an equable year-round climate, proximity to oceans, the presence of coastal mountains, and infrequent fire, they are among the most biologically productive places on earth.

These forests stand mainly in watersheds that empty directly into saltwater and, as a result, are fundamentally shaped by the cycling of water and nutrients between land and sea. Organic debris washes out of coastal watersheds, enhancing the productivity of marine ecosystems; salmon and other fish travel inland to spawn and die, transporting valuable nutrients with them. Evidence has been found for 137 animal species that depend upon salmon as a significant part of their diet.¹

Once found on five continents, coastal temperate rain forests have been modified throughout much of their original range. The North American coastal temperate rain forest, stretching from Northern California to Alaska, accounted for roughly fifty percent of the original global distribution of this forest type. Now, forty-four percent of the North American range has been developed. The impact of this development is abundantly evident from Vancouver Island south.

Industrial exploitation of the lands and waters of the coastal temperate rain forest has meant secure profits for a relative handful of corporate enterprises but insecure livelihoods for thousands of residents. Communities dependent on logging, mills, and coastal fisheries have seen their prosperity wax and wane with the boom-and-bust cycles typical of raw materials economies. In virtually every stretch of the eight thousand kilometer coastline that supports these forests around the world, residents are seeking to diversify local economies and to capture more of the value of the raw materials harvested and exported from the rain forest fringe.

More about the North American Coastal Temperate Rain Forest:

¹ Washington Department of Fish and Wildlife. Pacific Salmon and Wildlife: Ecological Contexts, Relationships, and Implications for Management. 2000.