Coast Range (EPA ecoregion)

This article is about the ecoregion designated by the EPA. For the mountains in California which are part of this ecoregion, see California Coast Ranges. For the mountains in Oregon which are part of this ecoregion, see Oregon Coast Range. For the mountains in Washington which are part of this ecoregion, see Olympic Mountains.

Coast Range ecoregion
From Ecola State Park, a view of coastal uplands (foreground) and volcanic mountains (background)
Level III ecoregions in the Pacific Northwest, with the Coast Range ecoregion marked as (1)
Ecology
Borders	Puget Lowland (2) Willamette Valley (3) Southern and Central California Chaparral and Oak Woodlands (6) North Cascades (77) Klamath Mountains (78)
Geography
Country	United States
States	Washington, Oregon and California
Coordinates	43°00′N 123°48′W / 43°N 123.8°W / 43; -123.8Coordinates: 43°00′N 123°48′W / 43°N 123.8°W / 43; -123.8

The Coast Range ecoregion is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in the U.S. states of Washington, Oregon, and California. It stretches along the Pacific Coast from the tip of the Olympic Peninsula in the north to the San Francisco Bay in the south, including Grays Harbor, Willapa Bay, and the Long Beach Peninsula in Washington, the entire length of the Oregon Coast, and the Northern California Coast. Named for the Coast Range mountains, it encompasses the lower elevations of the Olympic Mountains, the Oregon Coast Range, the Californian North Coast Ranges, and surrounding lowlands.^[1]^[2]

The low mountains of the ecoregion are covered by highly productive, rain-drenched evergreen forests that are home to the three tallest conifer species in the world: Coast redwood,^[3] Coast Douglas-fir,^[4] and Sitka spruce.^[5] Historically, Sitka spruce forests dominated the fog-shrouded coast, while a mosaic of western redcedar, western hemlock, and seral Douglas-fir blanketed the inland areas. Today, Douglas-fir plantations are prevalent on the intensively logged and managed landscape. Lithology influences land management strategies; slopes underlain by sedimentary rock are more susceptible to failure following clearcutting and road building than those underlain by volcanic rock.^[1]

The Coast Range ecoregion has been subdivided into fifteen Level IV ecoregions.

Level IV ecoregions

Level IV ecoregions in the Coast Range in Washington and Oregon. Contiguous areas in California have not been mapped yet. (Full map).

Coastal Lowlands (1a)

The Coastal Lowlands ecoregion contains beaches, sand dunes and spits, and low marine terraces below 400 feet (122 m) elevation. Characteristic features include wet forests, shallow freshwater lakes, estuarine marshes, and low-gradient, meandering tannic streams and rivers. Residential, commercial, and recreational developments are expanding in the coastal corridor. Many wetlands in the floodplains of the region's streams have been drained and converted into pastures for dairy farms, and associated stream degradation has occurred. Mature forests in the region are dominated by a canopy of Sitka spruce, western hemlock, and Douglas-fir, with salal, sword fern, vine maple, and Oregon grape in the shrub layer. The riparian zone supports red alder, western redcedar, and bigleaf maple with an understory of salmonberry; California bay-laurel is common in the south. Estuaries and coastal wetlands may feature Baltic rush, Lyngby’s sedge, tufted hairgrass, Pacific silverleaf, and seaside arrowgrass with shore pine, sweet gale, and Hooker’s willow. Stabilized dunes support shore pine over salal, rhododendron, and evergreen blueberry, with dune wildrye, Chilean strawberry, and dune bentgrass. Soil textures range from silty clay loam to sandy loam. The region covers 633 square miles (1,639 km²) in Oregon and 353 square miles (914 km²) in Washington, with the largest contiguous areas found near Grays Harbor, Willapa Bay, the mouth of the Columbia River, Tillamook Bay, and along the southern Oregon Coast. Public lands include the Grays Harbor, Willapa, Nestucca Bay, Siletz Bay, and Bandon Marsh National Wildlife Refuges, the Oregon Dunes National Recreation Area, and numerous state parks.^[1]^[2]

Coastal Uplands (1b)

The Coastal Uplands ecoregion includes the headlands, high marine terraces, hills, and low mountains surrounding the Coastal Lowlands, with medium to high gradient tannic streams. Elevation varies from 400 to 2500 feet (120 to 760 m). The climate is marine-influenced with an extended winter rainy season and minimal seasonal temperature extremes. Abundant fog during the summer dry season reduces vegetation moisture stress. The Uplands region roughly corresponds with the historic distribution of Sitka spruce. After extensive logging, most of the Sitka spruce is gone, and today the forests are dominated by Douglas-fir and western hemlock, with a shrub layer of salal, sword fern, vine maple, Oregon grape, rhododendron, and evergreen blueberry. Wetter slopes and riparian areas feature red alder, bigleaf maple, and western redcedar, with a salmonberry and currant understory. The headlands are covered by grasslands. The region is nearly three times the size of the Coastal Lowlands, covering 1,431 square miles (3,706 km²) in Washington and 1,117 square miles (2,893 km²) in Oregon. Public lands include the Drift Creek Wilderness, the Siuslaw National Forest, and the Lewis and Clark and Cape Meares national wildlife refuges. California has not been mapped yet.^[1]^[2]

Low Olympics (1c)

The Low Olympics ecoregion contains foothills and lower mountains of the Olympic Range, with U-shaped valleys and high gradient streams. It rises to an elevation of approximately 4,000 feet (1,219 m). Higher areas were glaciated. Copious precipitation (up to 200 inches (5,080 mm) a year) supports a lush, epiphyte-rich rainforest of western hemlock, western red cedar, and Douglas-fir, with Pacific silver fir at higher elevations. Riparian zones support red alder and bigleaf maple forests. Much of the region is in the third rotation of logging, including land within the Olympic National Forest. However, a portion of the region lies within Olympic National Park and contains ancient forests with extremely high biomass. The region covers 1,685 square miles (4,364 km²), entirely on the Olympic Peninsula of Washington. The higher elevations of the Olympic Mountains to the east are designated as part of the North Cascades ecoregion.^[2]

Volcanics (1d)

The Volcanics ecoregion consists of steeply sloping mountains and capes underlain by fractured basaltic rocks. Elevation generally varies from 600 to 4100 feet (180 to 1250 m), although in some places the volcanic rock extends down to sea level. The region is marked by columnar and pillow basalt outcrops. Its mountains may have been offshore seamounts engulfed by continental sediments about 200 million years ago. High gradient, cascading streams and rivers occur, and the basaltic substrate preserves summer flows that are more consistent than streams on the sedimentary rocks in surrounding ecoregions. The streams still support runs of spring chinook salmon and summer steelhead. The region's Douglas-fir plantations are heavily logged. Mature forests consist of Douglas-fir, western hemlock, salal, sword fern, vine maple, Oregon grape, and rhododendron. Wetter slopes and riparian areas may support western redcedar, bigleaf maple, red alder, salmonberry, and oxalis. Grassy coastal headlands and mountaintop balds feature Roemer’s fescue, thin bentgrass, California oatgrass, and diverse forbs. This large but disjunct ecoregion covers 2,043 square miles (5,291 km²) in Oregon and 1,542 square miles (3,994 km²) in Washington, including parts of the Olympic and Siuslaw National Forests and the Cummins Creek and Rock Creek Wildernesses, as well as higher elevations in the Cape Meares National Wildlife Refuge. California has not been mapped yet.^[1]^[2]

Outwash (1e)

The Outwash ecoregion is a gently sloping fan of glacial outwash material that forms a series of undulating terraces and plateaus. Elevation varies from 20 to 1000 feet (6 to 300 m). The region lies outside the zone of marine influence, and its medium gradient streams and rivers have lower summer flow than most other parts of the Coast Range. Mature forest types include Douglas-fir, western hemlock, red alder, bigleaf maple, and western red cedar, but today the region is largely dominated by industrial timber plantations. It is the smallest of the Coast Range subregions, covering 354 square miles (917 km²) in Grays Harbor County north of Aberdeen, Washington.^[2]

Willapa Hills (1f)

The Willapa Hills ecoregion (named for the Willapa Hills) consists of low, rolling hills and low, gently sloping mountains with medium gradient streams and rivers. It rises to an elevation of approximately 1,300 feet (396 m). This region has a lower drainage density than other upland areas in the Coast Range. Logging is relatively easy and less expensive in this accessible terrain, and industrial timberland has almost completely replaced the historic forests. When disturbed, the silt- and clay-textured soils are easily eroded, thereby degrading stream quality. The vegetation consists of Douglas-fir and western hemlock forests, with sword fern, vine maple, salal, Oregon grape, and rhododendron shrub layer. Wetter slopes and riparian areas support red alder, western redcedar, bigleaf maple, salmonberry, and oxalis. Large herds of Roosevelt elk winter in the region. The region covers 1,277 square miles (3,307 km²) in southwestern Washington and 751 square miles (1,945 km²) in northwestern Oregon, inland from the coast.^[1]^[2]

Mid-Coastal Sedimentary (1g)

The mountainous Mid-Coastal Sedimentary ecoregion lies outside of the coastal fog zone and is typically underlain by massive beds of sandstone and siltstone. Elevation varies from 300 to 3000 feet (90 to 900 m). The region is more rugged than the geologically similar Willapa Hills. Its Douglas-fir forests are intensively managed for logging, and the slopes are prone to failure when disturbed, particularly south of the Siuslaw River. Stream sedimentation is higher than in the Volcanics ecoregion. The mature forest consists of Douglas-fir and western hemlock, with salal, sword fern, vine maple, Oregon grape, and rhododendron; tanoak may be found on drier slopes to the south. Wetter slopes and riparian areas support bigleaf maple, western redcedar, grand fir, red alder, salmonberry, and oxalis, with California bay-laurel in the south. This is the largest of the Coast Range subregions, covering 3,739 square miles (9,684 km²) in the Central and Southern Oregon Coast Range.^[1]^[2]

Southern Oregon Coastal Mountains (1h)

The Southern Oregon Coastal Mountains ecoregion is a geologically and botanically diverse ecoregion that is a transition zone between the Coast Range and the Siskiyou Mountains, which form part of the Klamath Mountains ecoregion to the east. Rising to an elevation of approximately 4,000 feet (1,219 m), this region has the climate of the Coast Range but the varied lithology of the higher, more dissected Siskiyou Mountains, underlain by Jurassic sandstone, metamorphosed sediments, granite, and serpentinite. Distributions of northern and southern vegetation blend together here and species diversity is high. Douglas-fir, western hemlock, tanoak, Port Orford cedar, and western redcedar are present, along with salal, sword fern, vine maple, Oregon grape, rhododendron, California bay-laurel, bigleaf maple, grand fir, red alder, salmonberry, and oxalis. The region covers 692 square miles (1,792 km²) in a remote area of Curry County in southwestern Oregon containing the Sixes and Elk River drainages. It includes Grassy Knob Wilderness within the Siskiyou National Forest.^[1]^[2]

Redwood Zone (1i)

The low mountains of the Redwood Zone ecoregion lie entirely within the coastal fog zone. Elevation varies from 50 to 1800 feet (15 to 550 m). Historically, unbroken redwood forests moderated the local climate by trapping the coastal fog and producing shade. Remnants of unlogged redwood forest still survive east of Brookings, Oregon. Today, the region is characteristically covered by a mixed forest of coast redwood and Douglas-fir, with a shrub layer of vine maple, rhododendron, sword fern, and oxalis. The region covers 31 square miles (80 km²) in the far southwestern corner of Oregon. Larger sections in northwestern California have not been mapped yet.^[1]^[2]

Gallery

Flora

Coast Douglas-fir, Oregon's state tree
Sitka spruce logged in the Oregon Coast Range
Port Orford cedar, endemic to the Southern Oregon Coastal Mountains
Coast redwood trees in Northern California
Vine maple
Grasses help stabilize the Oregon Dunes.
Salmonberry blossom
Salal flowers

Fauna

Coho salmon
Douglas squirrel near the Oregon Coast
Snowy egret hunting fish
Black-tailed deer in the Northern Oregon Coast Range

Landscapes

Rock Creek Wilderness supports salmon, steelhead, and cutthroat trout.
Clearcutting and road building, as in this area near the source of the Lewis and Clark River, may contribute to slope failure and affect surface water quality.
Olympic rainforests have the highest living biomass density on earth.
The dynamic Lanphere Dunes in Humboldt County exemplify the coastal dune forest ecosystem.

References

↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 This article incorporates public domain material from the United States Geological Survey document: Thorson, T.D., Bryce, S.A., Lammers, D.A. et al. "Ecoregions of Oregon". (color poster with map, descriptive text, summary tables, and photographs; with a Reverse side).
↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 This article incorporates public domain material from the United States Geological Survey document: Pater, D., Bryce, S.A., Kagan, J. et al. "Ecoregions of Western Washington and Oregon". (color poster with map, descriptive text, summary tables, and photographs; with a Reverse side).
↑ "Gymnosperm Database: Sequoia sempervirens". Retrieved 2012-02-05.
↑ "Gymnosperm Database: Pseudotsuga menziesii". Retrieved 2012-02-05.
↑ "Gymnosperm Database: Picea sitchensis". Retrieved 2012-02-05.

Level III Ecoregions in the United States

Marine West Coast Forest	1 Coast Range 2 Puget Lowland 3 Willamette Valley 111 Ahklun and Kilbuck Mountains 113 Alaska Peninsula Mountains 115 Cook Inlet 119 Pacific Coastal Mountains 120 Coastal Western Hemlock-Sitka Spruce Forests

Northwestern Forested Mountains	4 Cascades 5 Sierra Nevada 9 Eastern Cascades Slopes and Foothills 11 Blue Mountains 15 Northern Rockies 16 Idaho Batholith 17 Middle Rockies 19 Wasatch and Uinta Mountains 21 Southern Rockies 41 Canadian Rockies 77 North Cascades 78 Klamath Mountains 105 Interior Highlands 116 Alaska Range 117 Copper Plateau 118 Wrangell Mountains

Mediterranean California	6 Southern and Central California Chaparral and Oak Woodlands 7 Central California Valley 8 Southern California Mountains

North American Deserts	10 Columbia Plateau 12 Snake River Plain 13 Central Basin and Range 14 Mojave Basin and Range 18 Wyoming Basin 20 Colorado Plateaus 22 Arizona/New Mexico Plateau 24 Chihuahuan Deserts 80 Northern Basin and Range 81 Sonoran Basin and Range

Temperate Sierras	23 Arizona/New Mexico Mountains

Great Plains	25 Western High Plains 26 Southwestern Tablelands 27 Central Great Plains 28 Flint Hills 29 Central Oklahoma/Texas Plains 30 Edwards Plateau 31 Southern Texas Plains 34 Western Gulf Coastal Plain 40 Central Irregular Plains 42 Northwestern Glaciated Plains 43 Northwestern Great Plains 44 Nebraska Sand Hills 45 Piedmont 46 Northern Glaciated Plains 47 Western Corn Belt Plains 48 Lake Agassiz Plain

Eastern Temperate Forest	32 Texas Blackland Prairies 33 East Central Texas Plains 35 South Central Plains 36 Ouachita Mountains 37 Arkansas Valley 38 Boston Mountains 39 Ozark Highlands 51 North Central Hardwood Forests 52 Driftless Area 53 Southeastern Wisconsin Till Plains 54 Central Corn Belt Plains 55 Eastern Corn Belt Plains 56 Southern Michigan/Northern Indiana Drift Plains 57 Huron/Erie Lake Plains 59 Northeastern Coastal Zone 60 Northern Appalachian Plateau and Uplands 61 Erie Drift Plain 63 Middle Atlantic Coastal Plain 64 Northern Piedmont 65 Southeastern Plains 66 Blue Ridge 67 Ridge and Valley 68 Southwestern Appalachians 69 Central Appalachians 70 Western Allegheny Plateau 71 Interior Plateau 72 Interior River Valleys and Hills 73 Mississippi Alluvial Plain 74 Mississippi Valley Loess Plains 75 Southern Coastal Plain 82 Laurentian Plains and Hills 83 Eastern Great Lakes and Hudson Lowlands 84 Atlantic Coastal Pine Barrens

Northern Forests	49 Northern Minnesota Wetlands 50 Northern Lakes and Forests 58 Northeastern Highlands 62 North Central Appalachians

Tropical Wet Forests	76 Southern Florida Coastal Plain

Southern Semi-Arid Highlands	79 Madrean Archipelago

Taiga	101 Arctic Coastal Plain 102 Arctic Foothills 103 Brooks Range 104 Interior Forested Lowlands and Uplands 106 Interior Bottomlands 107 Yukon Flats 108 Ogilvie Mountains

Tundra	109 Subarctic Coastal Plains 110 Seward Peninsula 112 Bristol Bay-Nushagak Lowlands 114 Aleutian Islands

as defined by the United States Environmental Protection Agency

Level III Ecoregions in Oregon

Marine West Coast Forest	1 Coast Range 3 Willamette Valley

Northwestern Forested Mountains	4 Cascades 9 Eastern Cascades Slopes and Foothills 11 Blue Mountains 78 Klamath Mountains

North American Deserts	10 Columbia Plateau 12 Snake River Plain 80 Northern Basin and Range

as defined by the United States Environmental Protection Agency