Willamette Valley (ecoregion)
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Willamette Valley (ecoregion)
The Willamette Valley ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency in the U.S. states of Oregon and Washington. Slightly larger than the Willamette Valley for which it is named, the ecoregion contains fluvial terraces and floodplains of the Willamette River system, scattered hills, buttes, and adjacent foothills. It is distinguished from the neighboring Coast Range, Cascades, and Klamath Mountains ecoregions by lower precipitation, lower elevation, less relief, and a different mosaic of vegetation. Mean annual rainfall is 37 to 60 inches (96 to 152 cm), and summers are generally dry. Historically, the region was covered by rolling prairies, oak savanna, coniferous forests, extensive wetlands, and deciduous riparian forests. Today, it contains the bulk of Oregon's population, industry, commerce, and agriculture. Productive soils and a temperate climate make it one of the most important agricultural areas in Oregon. ...
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Wetlands
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The primary factor that distinguishes wetlands from terrestrial land forms or Body of water, water bodies is the characteristic vegetation of aquatic plants, adapted to the unique anoxic hydric soils. Wetlands are considered among the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal species. Methods for assessing wetland functions, wetland ecological health, and general wetland condition have been developed for many regions of the world. These methods have contributed to wetland conservation partly by raising public awareness of the functions some wetlands provide. Wetlands occur naturally on every continent. The water in wetlands is either freshwater, brackish or saltwater. The main wetland ty ...
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Floodplain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudie, A. S., 2004, ''Encyclopedia of Geomorphology'', vol. 1. Routledge, New York. The soils usually consist of clays, silts, sands, and gravels deposited during floods. Because the regular flooding of floodplains can deposit nutrients and water, floodplains frequently have high soil fertility; some important agricultural regions, such as the Mississippi river basin and the Nile, rely heavily on the flood plains. Agricultural regions as well as urban areas have developed near or on floodplains to take advantage of the rich soil and fresh water. However, the risk of flooding has led to increasing efforts to control flooding. Formation Most floodplains are formed by deposition on the inside of river meanders and by overbank flow. Whereve ...
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Mixed Forest Wilsonville
Mixed is the past tense of ''mix''. Mixed may refer to: * Mixed (United Kingdom ethnicity category), an ethnicity category that has been used by the United Kingdom's Office for National Statistics since the 1991 Census * ''Mixed'' (album), a compilation album of two avant-garde jazz sessions featuring performances by the Cecil Taylor Unit and the Roswell Rudd Sextet See also * Mix (other) * Mixed breed, an animal whose parents are from different breeds or species * Mixed ethnicity Mixed race people are people of more than one race or ethnicity. A variety of terms have been used both historically and presently for mixed race people in a variety of contexts, including ''multiethnic'', ''polyethnic'', occasionally ''bi-ethn ...
, a person who is of multiple races * * {{disambiguation ...
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Oregon Oak Grove
Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. The 42° north parallel delineates the southern boundary with California and Nevada. Oregon has been home to many indigenous nations for thousands of years. The first European traders, explorers, and settlers began exploring what is now Oregon's Pacific coast in the early-mid 16th century. As early as 1564, the Spanish began sending vessels northeast from the Philippines, riding the Kuroshio Current in a sweeping circular route across the northern part of the Pacific. In 1592, Juan de Fuca undertook detailed mapping and studies of ocean currents in the Pacific Northwest, including the Oregon coast as well as the strait now bearing his name. Spanish ships – 250 in as many years – would typically not land before reaching Cape Mendocino i ...
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Portland, Oregon
Portland (, ) is a port city in the Pacific Northwest and the largest city in the U.S. state of Oregon. Situated at the confluence of the Willamette and Columbia rivers, Portland is the county seat of Multnomah County, the most populous county in Oregon. Portland had a population of 652,503, making it the 26th-most populated city in the United States, the sixth-most populous on the West Coast, and the second-most populous in the Pacific Northwest, after Seattle. Approximately 2.5 million people live in the Portland metropolitan statistical area (MSA), making it the 25th most populous in the United States. About half of Oregon's population resides within the Portland metropolitan area. Named after Portland, Maine, the Oregon settlement began to be populated in the 1840s, near the end of the Oregon Trail. Its water access provided convenient transportation of goods, and the timber industry was a major force in the city's early economy. At the turn of the 20th century, the ...
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Cascades Range
The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades. The small part of the range in British Columbia is referred to as the Canadian Cascades or, locally, as the Cascade Mountains. The latter term is also sometimes used by Washington residents to refer to the Washington section of the Cascades in addition to North Cascades, the more usual U.S. term, as in North Cascades National Park. The highest peak in the range is Mount Rainier in Washington at . part of the Pacific Ocean's Ring of Fire, the ring of volcanoes and associated mountains around the Pacific Ocean. All of the eruptions in the contiguous United States over the last 200 years have been from Cascade volcanoes. The two most recent were Lassen Peak from 1914 to 1921 and a major e ...
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Oregon Coast Range
The Oregon Coast Range, often called simply the Coast Range and sometimes the Pacific Coast Range, is a mountain range, in the Pacific Coast Ranges physiographic region, in the U.S. state of Oregon along the Pacific Ocean. This north-south running range extends over from the Columbia River in the north on the border of Oregon and Washington, south to the middle fork of the Coquille River. It is wide and averages around in elevation above sea level. The coast range has three main sections, a Northern, Central, and Southern. The oldest portions of the range are over 60 million years old, with volcanics and a forearc basin as the primary mountain building processes responsible for the range. It is part of the larger grouping known as the Pacific Coast Ranges that extends over much of the western edge of North America from California to Alaska. The range creates a rain shadow effect for the Willamette Valley that lies to the east of the mountains, creating a more stable climate a ...
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Columbia River
The Columbia River (Upper Chinook: ' or '; Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada. It flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state of Oregon before emptying into the Pacific Ocean. The river is long, and its largest tributary is the Snake River. Its drainage basin is roughly the size of France and extends into seven US states and a Canadian province. The fourth-largest river in the United States by volume, the Columbia has the greatest flow of any North American river entering the Pacific. The Columbia has the 36th greatest discharge of any river in the world. The Columbia and its tributaries have been central to the region's culture and economy for thousands of years. They have been used for transportation since a ...
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Temperate Climate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout the year and more distinct seasonal changes compared to tropical climates, where such variations are often small and usually only have precipitation changes. In temperate climates, not only do latitudinal positions influence temperature changes, but sea currents, prevailing wind direction, continentality (how large a landmass is) and altitude also shape temperate climates. The Köppen climate classification defines a climate as "temperate" C, when the mean temperature is above but below in the coldest month to account for the persistency of frost. However, other climate classifications set the minimum at . Zones and climates The north temperate zone extends from the Tropic of Cancer (approximately 23.5° north latitude) to the Arctic ...
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Riparian Forest
A riparian forest or riparian woodland is a forested or wooded area of land adjacent to a body of water such as a river, stream, pond, lake, marshland, estuary, canal, sink or reservoir. Etymology The term riparian comes from the Latin word ''ripa'', 'river bank'; technically it only refers to areas adjacent to flowing bodies of water such as rivers, streams, sloughs and estuaries. However, the terms ''riparian forest'' and ''riparian zone'' have come to include areas adjacent to non-flowing bodies of water such as ponds, lakes, playas and reservoirs. Characteristics Riparian forests are subject to frequent inundation. Riparian forests help control sediment, reduce the damaging effects of flooding and aid in stabilizing stream banks. Riparian zones are transition zones between an upland terrestrial environment and an aquatic environment. Organisms found in this zone are adapted to periodic flooding. Many not only tolerate it, but require it in order to maintain health an ...
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Temperate Coniferous Forest
Temperate coniferous forest is a terrestrial biome defined by the World Wide Fund for Nature. Temperate coniferous forests are found predominantly in areas with warm summers and cool winters, and vary in their kinds of plant life. In some, needleleaf trees dominate, while others are home primarily to broadleaf evergreen trees or a mix of both tree types. A separate habitat type, the tropical coniferous forests, occurs in more tropical climates. Temperate coniferous forests are common in the coastal areas of regions that have mild winters and heavy rainfall, or inland in drier climates or montane areas. Many species of trees inhabit these forests including pine, cedar, fir, and redwood. The understory also contains a wide variety of herbaceous and shrub species. Temperate coniferous forests sustain the highest levels of biomass in any terrestrial ecosystem and are notable for trees of massive proportions in temperate rainforest regions. Structurally, these forests are rather si ...
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Oak Savanna
An oak savanna is a type of savanna—or lightly forested grassland—where oaks (''Quercus ''spp.) are the dominant trees. The terms "oakery" or "woodlands" are also used commonly, though the former is more prevalent when referencing the Mediterranean area. These savannas were maintained historically through wildfires set by lightning, humans, grazing, low precipitation, and/or poor soil. Although there are pockets of oak savanna almost anywhere in North America where oaks are present, there are three major oak savanna areas: 1) California, British Columbia, Washington and Oregon in the west; 2) Southwestern United States and northern Mexico; and 3) the prairie/forest border of the Midwestern United States. There are also small areas of oak savannas in other parts of the world. (See also Eastern savannas of the United States for information on pine savannas of the U.S. South.) Midwestern oak savannas The oak savannas of the Midwestern United States form a transition zone betw ...
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