History of The Pacific Northwest - Ecoregions

Ecoregions

Much of the Pacific Northwest is forested. The Georgia Strait–Puget Sound basin is shared between British Columbia and Washington, and the Pacific temperate rain forests ecoregion, which is the largest of the world's temperate rain forest ecozones in the system created by the World Wildlife Fund, stretches along the coast from Alaska to California. The dryland area inland from the Cascade Range and Coast Mountains is very different from the terrain and climate of the coastal area due to the rain shadow effect of the mountains, and comprises the Columbia, Fraser and Thompson Plateaus and mountain ranges contained within them. The interior regions' climates largely within eastern Washington, south central British Columbia, eastern Oregon, and southern Idaho are a northward extension of the Great Basin Desert, which spans the Great Basin farther south, although by their northern and eastern reaches, dryland and desert areas verge at the end of the Cascade's rain shadow with the boreal forest and various alpine flora regimes characteristic of eastern British Columbia,north Idaho and western Montana roughly along a longitudinal line defined by the Idaho border with Washington and Oregon.