North Pacific Maritime
Dense coniferous forests of western red cedar, spruce, and giant Douglas fir—among the largest trees on Earth—dominate the steep, rugged ranges that stretch from central Oregon to southern Alaska. The ocean’s moderating influence and the high coastal mountains produce a damp climate with mild winters and cool summers. The foothills give way to a narrow coastal plain punctuated by slender bays, alluvial fans, and tidal estuaries and deltas. The ecological and cultural value of the region’s most famous fish have led some to call this land “salmon nation.”
Location
Extends from Kodiak Island, Alaska south through coastal Alaska, British Columbia, Washington, Oregon, and northeastern California.
Climate
Due to Pacific weather patterns, climate is relatively mild with humid to wet climate along throughout. Mean annual temperatures of 10ºC,(50ºF) with annual precipitation averaging 1050mm (41 inches) when measured at Vancouver, BC
Features
High mountains throughout, with deep inter-montane valleys in selected locations. Glaciers cap high mostly-volcanic mountains, and in coastal Alaska extend down to the ocean. Large inland valleys include the Puget Trough, Georgia Lowlands, and Willamette Valley. Temperate rainforest of Douglas fir, sitka spruce, and western hemlock dominate montane slopes and lowlands. Dry-mesic mixed conifer forests predominate the margins of the Willamette Valley and adjacent drier mountainsides. Garry Oak woodland and grasslands – as well as wet prairies - historically characterized the valley floors, now largely converted for agriculture and urban development.
History and Trends
Indigenous cultures centered on fishing; likely used fire in the interior valleys for hunting and trail maintenance. Agriculture, and especially viticulture – has become well-established. Throughout the mountains, past focus on natural resource industry -- mining, logging, and fishing -- have diminished as urban growth and technical industries have taken precedence. Major population centers are Seattle and Portland.
Pacific Maritime Ecoregions
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Modoc Plateau and East Cascades
The Upper Klamath Basin and the Modoc Plateau are large land forms that characterize the southern portion of the ecoregion. The Modoc Plateau has a diverse geography, with portions draining into closed basins such as Goose Lake and Surprise Valley, and most of the remainder draining into the Pitt River, a tributary of the Sacramento River.
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North Cascades Ecoregion
In the United States, the North Cascades Ecoregion features the high, rugged mountains of the Pacific Ranges. The Washington portion of the ecoregion contains the greatest concentration of active glaciers in the 48 conterminous United States.
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Pacific Northwest Coast
The Pacific Northwest Coast ecoregion includes most of the Olympic Peninsula of Washington, the coast mountain ranges extending down to central Oregon, and most of Vancouver Island in British Columbia.
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West Cascades
The West Cascades Ecoregion extends west from the Cascade Crest to the Puget Sound and Willamette Valley lowlands and from Snoqualmie Pass south across the Columbia Gorge to the Klamath Mountains in southwest Oregon, almost to the California border.
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Willamette Valley-Puget Trough-Georgia Basin Ecoregion
The Willamette Valley-Puget Trough-Georgia Basin ecoregion is a long ribbon of broad valley lowlands and inland sea flanked by the rugged Cascade and coastal mountain ranges of British Columbia, Washington, and Oregon.