- Eastern Cascades Slopes and Foothills (ecoregion)
The Eastern Cascades Slopes and Foothills ecoregion is a Level III ecoregion designated by the
United States Environmental Protection Agency(EPA) in the U.S. statesof Oregon, Washington, and California. In the rain shadowof the Cascade Range, the eastern side of the mountains experiences greater temperature extremes and receives less precipitationthan the west side. Open forests of ponderosa pineand some lodgepole pinedistinguish this region from the Cascades ecoregion, where hemlock and firforests are more common, and from the lower, drier ecoregions to the east, where shrubs and grasslands are predominant. The vegetationis adapted to the prevailing dry, continental climateand frequent wildfire. Volcanic cones and buttes are common in much of the region.Citation | last=Thorson | first=T.D. | last2=Bryce | first2=S.A. | last3=Lammers | first3=D.A. | last4=et al. | title=Ecoregions of Oregon (color poster with map, descriptive text, summary tables, and photographs) | place=Reston, Virginia | publisher= United States Geological Survey| year=2003 | url=ftp://ftp.epa.gov/wed/ecoregions/or/or_front.pdf (and the [ftp://ftp.epa.gov/wed/ecoregions/or/or_back.pdf Reverse side] ) Many sentences in this article are copied verbatim from the source, which is in the public domain.] Citation | last=Pater | first=David | last2=Bryce | first2=S.A. | last3=Kagan | first3=Jimmy | last4=et al. | title=Ecoregions of Western Washington and Oregon (color poster with map, descriptive text, summary tables, and photographs) | place=Reston, Virginia | publisher= United States Geological Survey| url=ftp://ftp.epa.gov/wed/ecoregions/or_wa_id/ORWAFront90.pdf (and the [ftp://ftp.epa.gov/wed/ecoregions/or_wa_id/ORWABack.pdf Reverse side] ) Many sentences in this article are copied verbatim from the source, which is in the public domain.]
The Eastern Cascades Slopes and Foothills ecoregion has been subdivided into ten Level IV ecoregions, as described below. Level IV mapping is not yet complete in California, and the information below includes only the sections in Washington and Oregon.
Level IV ecoregions
Yakima Plateau and Slopes (9a)
The high, unglaciated Yakima Plateau and Slopes ecoregion is characterized by
plateaus, buttes, and canyons, with medium to high gradient permanent and intermittent streams and rivers on a surface of basalt. Natural springs occur, especially in the south. Elevation varies from 2500 to 5000 feet (762 to 1524 m). The dry continental climate supports open woodlands dominated by ponderosa pine and bitterbrush, with some Douglas-firand Oregon white oak. Fire is an integral part of the ecosystem. The region covers convert|1793|sqmi|km2|0 in Washington, mainly on land belonging to the Yakama Nation.
Grand Fir Mixed Forest (9b)
The Grand Fir Mixed Forest ecoregion is characterized by high, glaciated plateaus,
mountains, and canyons containing high gradient streams and rivers. Scattered lakes occur in glacial rock basins. Elevation varies from 2200 to 6500 feet (671 to 1829 m). The frigid soils and snowy, continental climate support a mix of grand firand Douglas-fir, with some ponderosa pine and western larch. Plants in the understoryinclude vine maple, hazel, snowberry, and oceanspray. The region covers convert|812|sqmi|km2|0 in Washington and convert|162|sqmi|km2|0 in Oregon, on the eastern slopes of Mount Rainier, Mount Adams, and Mount Hood, and on Black Butte. It contains land belonging to the Yakama Nation and public land within the Wenatchee, Gifford Pinchot, Deschutes, and Mount Hood National Forests (including the Badger Creek Wilderness).
Oak/Conifer Foothills (9c)
The Oak/Conifer Foothills ecoregion is lower and drier than the Grand Fir Mixed Forest and more diverse than other parts of the Eastern Cascades. It consists of foothills, low mountains, plateaus, and valleys from 500 to 3500 feet (152 to 1067 m). Marine weather enters the region via the
Columbia River Gorge, moderating the otherwise continental climate. As a result, soil, climate, and vegetation share characteristics of both eastern and western Oregon. The region is characterized by Oregon white oak woodlands and ponderosa pine forests in the east and Douglas-fir and western hemlockforests in the west. Some grasslands also occur. Understory plants include Idaho fescue, bluebunch wheatgrass, antelope bitterbrush, Oregon grape, hazel, and snowberry. Common land uses include forestry, recreation, grazing, rural residential development, orchards, and, in the valleys, grain and hay farming. The land is mostly privately owned. The region covers convert|563|sqmi|km2|0 in Washington and convert|461|sqmi|km2|0 in Oregon along the Columbia Rivercorridor, including the lower reaches of the White Salmon and Klickitat Riverdrainages.
Ponderosa Pine/Bitterbrush Woodland (9d)
The Ponderosa Pine/Bitterbrush Woodland ecoregion has a terrain dominated by high, undulating volcanic plateaus and canyons, with permanent, medium gradient streams. Elevation varies from 2400 to 5200 feet (732 to 1585 m). Stream flow is consistent year-round, due to the volcanic
hydrogeology. The well-drained, frigid soils are derived from Mount Mazama volcanic ashand support nearly homogenous stands of ponderosa pine. Historically, frequent fires burned undergrowth, creating open groves of pines. Lodgepole pine is largely absent here. Understory vegetation varies with elevation; at lower elevations, antelope bitterbrush is important winter browse for deer. At higher elevations, greenleaf manzanitaand snowberry are found. Riparian areas support mountain alder, stream dogwood, willows, and sedges. The region covers convert|1077|sqmi|km2|0 in Oregon, east of Mount Jefferson, Three-Fingered Jack, and the Three Sisters, in the Deschutes National Forestand on the Warm Springs Indian Reservation.
Pumice Plateau (9e)
The Pumice Plateau ecoregion is a high volcanic plateau, characteristically covered by thick deposits of Mount Mazama ash and
pumice. Elevation varies from 4200 to 8300 feet (1280 to 2530 m). Residual soils are very deep, highly permeable, and subject to drought, with intermittent, low to medium gradient streams and spring-fed creeks and marshes. Freezing temperatures are possible any time of year. Ponderosa pine forests are common on slopes, with white firat higher elevations. Colder depressions and flats, where pumice deposits are thickest, are dominated by lodgepole pine, with an understory of antelope bitterbrush and Idaho fescue. Riparian areas support mountain alder, stream dogwood, willows, and quaking aspen. The Pumice Plateau is the largest of the Eastern Cascades subregions, covering convert|4236|sqmi|km2|0 in Oregon between Bend and Klamath Falls. It contains extensive areas within the Deschutes and Fremont-Winema National Forests (including the Gearhart Mountain Wilderness) and the lower elevations of the Newberry National Volcanic Monument.
Cold Wet Pumice Plateau Basins (9f)
The Cold Wet Pumice Plateau Basins ecoregion includes
Sycan Marsh, Klamath Marsh, and La Pine Basin, which are surrounded by the Pumice Plateau but have have distinct vegetation and topography. At an elevation of 4100 to 5200 feet (1250 to 1585 m), they function as cold air catch-basins during the winter, which results in lower minimum temperatures. Soils in the basins have water tables at or near the surface for significant periods of the year, in contrast to the soils of the Pumice Plateau. The La Pine Basin is underlain by thick lacustrinedeposits that exhibit high groundwaterlevels during the spring snowmelt. It supports lodgepole pine stands, as well as wet, forested wetlands of lodgepole pine, willow, and aspen. Scattered ponderosa pine shrub forest is found on the driest soils. The Sycan and Klamath marshes support wetland meadowvegetation, including tules and tufted hairgrass. Marshes, lakes, reservoirs, wetland forests, and medium and low gradient rivers provide important habitat for migratory waterfowl. The region covers convert|651|sqmi|km2|0 in Oregon, a mixture of private and public lands, including the Deschutes and Fremont-Winema National Forests and the Klamath Marsh National Wildlife Refuge.
Klamath/Goose Lake Warm Wet Basins (9g)
The Klamath/Goose Lake Warm Wet Basins ecoregion (named for Upper Klamath and Goose lakes) is drier than elsewhere in the eastern Cascades, yet it contains
floodplains, terraces, and a pluvial lakebasin. Elevation varies from 4000 to 5400 feet (1219 to 1646 m). A variety of wildrye, bluegrass, and wheatgrass species once covered the basins, but most of the wet meadows and wetlands have been drained for rural residential development, pasture, and cropland, including alfalfa, potatoes, and small grains. Potential vegetation includes bluebunch wheatgrass, Idaho fescue, antelope bitterbrush, big sagebrush, and low sagebrushon the steppes, with tules, cattails, and sedges in the wetlands. Several marshland wildlife refuges within the Klamath Basin National Wildlife Refuges Complexare key to preserving regional biodiversity, particularly at-risk bird and fish species. The region covers convert|1039|sqmi|km2|0 in Klamath and Lake counties, Oregon. Contiguous areas in California have not been mapped yet.
Fremont Pine/Fir Forest (9h)
The Fremont Pine/Fir Forest ecoregion contains steeply to moderately sloping mountains and high plateaus that rarely exceed timberline. Elevation varies from 5000 to 8000 feet (1524 to 2439 m). Residual soils are common in the region, in contrast to the Pumice Plateau, where soils have been deeply buried by pumice and ash. Reservoirs, a few glacial rock-basin lakes, many springs, and high gradient intermittent and ephemeral streams occur. The continental climate and diverse terrain support a range of vegetation types. Ponderosa pine and
western juniperwoodlands are common at lower elevations. White fir, sugar pine, whitebark pine, lodgepole pine, and California incense-cedarare found on north slopes and at higher elevations. Understory plants include snowberry, heartleaf arnica, Wheeler bluegrass, antelope bitterbrush, and longstolon sedge. The region covers convert|1672|sqmi|km2|0 in Oregon, mainly on public land within the Fremont-Winema National Forest. Contiguous areas in California have not been mapped yet.
outhern Cascades Slope (9i)
The Southern Cascades Slope ecoregion is a transitional zone between the Cascades ecoregion and the drier Eastern Cascade Slopes and Foothills, characterized by moderately sloping mountains with medium to high gradient streams. Elevation varies from 3600 to 6300 feet (1097 to 1920 m). It is higher than other subregions in the Eastern Cascades and typically receives greater precipitation. Forests of ponderosa pine blanket the mountainous landscape; white fir, Shasta red fir, Douglas-fir, and incense cedar grow at higher elevations. Understory plants include Idaho fescue, antelope bitterbrush,
Ross' sedge, western fescue, snowberry, and golden chinkapin. The region covers convert|515|sqmi|km2|0 in Oregon, south of Aspen Buttein the Klamath Riverwatershed, including Bear Valley National Wildlife Refuge. Contiguous areas in California have not been mapped yet.
Klamath Juniper Woodland (9j)
The Klamath Juniper Woodland ecoregion is composed of undulating hills, benches, and
escarpments covered with a mosaic of rangelandand woodland, at an elevation of 4400 to 6200 feet (1341 to 1890 m). Mean annual precipitation ranges from 12 to 20 inches (30 to 51 cm) per year. Western juniper grows on shallow, rocky soils with an understory of low sagebrush, Wyoming big sagebrush, bitterbrush, and bunchgrasses. Several species found in the shrub-steppegrasslands are uncommon in eastern Oregon, such as woolly wyethia, Klamath plum, and birchleaf mountain-mahogany. The diverse shrublands provide important wildlife habitat. Reservoirs dot the landscape and are important to lowland irrigation. The region covers convert|784|sqmi|km2|0 in Oregon, south of Klamath Falls in the Lost River watershed, a mixture of public and private land. Contiguous areas in California have not been mapped yet.
*Ecoregions defined by the EPA and the
Commission for Environmental Cooperation:
List of ecoregions in North America (CEC)
List of ecoregions in the United States (EPA)
List of ecoregions in Oregon
List of ecoregions in Washington
List of ecoregions in California
*The conservation group
World Wildlife Fundmaintains an alternate classification system:
List of ecoregions (WWF)
List of ecoregions in the United States (WWF)
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