Characteristics of the Coastal Temperate Rain Forest
Coastal temperate rain forests are found in wet, cool climates where the collision of marine air and coastal mountains causes large amounts of rainfall. The worldwide distribution of coastal temperate rain forests has always been limited and today much of their remaining thirty to forty million hectares is located in Chile and along the Pacific Northwest of North America.
Realization of the uniqueness of coastal temperate rain forests has come quite recently. Although scientists have recognized temperate rain forests for over fifty years, the term "coastal" temperate rain forest has a scientific currency of just a decade. Knowledge of these forests and interest in the bioregions where they stand are now growing rapidly.
In 1990, ecologists Paul Alaback and James Weigand proposed four features to distinguish coastal rain forests from other temperate forest types: proximity to oceans, the presence of coastal mountains, cooler summer temperatures, and higher rainfall levels with significant precipitation occurring in all seasons. These conditions lead to a unique set of dynamic links between terrestrial and marine ecosystems. In effect, the high tide line does not bound the coastal rain forest ecosystem: the forest influences the abundance and distribution of coastal sea life, and a number of animal species return the favor by carrying marine nutrients back into coastal watersheds.
Coastal temperate rain forests foster a hugely disproportionate share of the world's biological production. They accumulate and store more organic matter than any other forest type (including tropical rain forests) - as much as 500-2,000 metric tons of wood, foliage, leaf litter, moss, other living plants, and organic soil per hectare. Some individual trees in temperate rain forests have grown for two millennia and surpass six meters in diameter. The adjacent waters are productive as well. The upwelling zones and cold-water currents that bathe the edges of coastal temperate rain forests account for a substantial share of the biological production of the oceans. The productivity of these marine ecosystems is enhanced by the nutrients and organic debris washed out of the coastal watersheds.
The largest contiguous coastal temperate rain forest traces the northwestern maritime margin of North America, from Kodiak Island in Alaska south through British Columbia and the U.S. Pacific Northwest to California's "fogbelt" redwoods. Elsewhere in the northern hemisphere, Norway contains small fragments of coastal rain forest, but the forests formerly found along the west coasts of Ireland and Scotland, in parts of Iceland, and in a narrow crescent along the eastern shore of the Black Sea are long gone. Chile contains the Southern Hemisphere's largest remaining coastal temperate rain forest. Significant areas of coastal rain forest also stand on the west coast of New Zealand's South Island and on the Australian island of Tasmania.
Throughout their original distribution, the fecundity and relatively mild maritime climates of coastal temperate rain forest regions have invited heavy exploitation. Coastal rain forests were among the first landscapes logged when Euro-Americans settled North America's Pacific Coast in the 1850s. Clearcut logging of old-growth conifers remains widespread in this region today, and many rain forest valleys have become industrial tree farms from which trees have already been harvested three times.
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.
The growing importance of recreation, tourism, and environmental services in the economies of many coastal areas as well as the recognition that methods of conventional resource extraction deplete natural capital are forcing a reappraisal of resource-based industries and the landscapes they leave behind. New insights into the interdependence of land and sea in the coastal rain forest zone offer further challenges to traditional management practices. The connections between forestry and fisheries offer an obvious example: the true contribution of logging to local economies is exaggerated by the extent to which associated road building alters the flows of nutrients and sediment and thereby reduces greatly the production of coastal fisheries. Further research will guide communities seeking to understand such tradeoffs.
