Coastal Temperate Rain Forest, Original Distribution
Keywords: Forests
(An excerpt from The Rain Forests of Home: An Atlas of People and Place)
The forests along the western coast of North America from the redwoods in California to Alaska's Kodiak Island contain approximately half of the remaining worldwide distribution of coastal temperate rain forest. Ecologist Paul Alaback (1991, 1995) distinguishes four coastal rain forest zones in North America based on temperature and precipitation distribution, which are the primary determinants of the distribution of plants and animals. This map shows the probable pre-European settlement distribution of conifer forests and associated vegetation types (bogs, muskegs, and high-elevation areas) that make up the North American coastal temperate rain forest.
Several sets of climate data (precipitation and temperature) and elevation information, augmented by land cover data, were combined to estimate the original extent of coastal temperate rain forest in the United States portion of the bioregion. For British Columbia, the coastal western hemlock biogeoclimatic zone provided a preferred indication of original distribution. The coast redwood range, a drier zone of coastal temperate rain forest, was also mapped using information on the major vegetation zones of California. The sub-polar, perhumid and seasonal rain forest zones distinguished within the coastal temperate rain forest were delimited based on the expert knowledge of several leading ecologists.
Highlights:
- Changes in climate and physiography from north to south change the character of the forest. The rugged relief of the far north creates a steep climatic gradient that confines the forest to a narrow coastal strip.
- Each zone supports distinct associations of dominant species. Sitka spruce and western and mountain hemlock dominate the subpolar zone. Sitka spruce, western red cedar, and western hemlock characterize the perhumid zone. Douglas-fir joins these species as a dominant in the seasonal zone. Coast redwood distinguishes the redwood zone.
Map by: Pacific GIS
Created: January 1, 1995
