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Forest Park is a public municipal park in the Tualatin Mountains west of downtown Portland, Oregon, United States. Stretching for more than on hillsides overlooking the Willamette River, it is one of the country's largest urban forest reserves. The park, a major component of a regional system of parks and trails, covers more than of mostly second-growth forest with a few patches of old growth. About of recreational trails, including the Wildwood Trail segment of the city's 40 Mile Loop system, crisscross the park. As early as the 1860s, civic leaders sought to create a natural preserve in the woods near Portland. Their efforts led to the creation of a municipal park commission that in 1903 hired the Olmsted Brothers landscape architectural firm to develop a plan for Portland's parks. Acquiring land through donations, transfers from Multnomah County, and delinquent tax foreclosures, the city eventually acted on a proposal by the City Club of Portland and combined parcels totaling about to create the reserve. Formally dedicated in 1948, it ranks 19th in size among parks within U.S. cities, according to The Trust for Public Land.〔 The Trust for Public Land (TPL) lists the size of the park as , which is close to its original size of 1948. If the size claimed by the Portland Parks & Recreation Department in 2009 were used in the TPL listing, Forest Park would rank 17th.〕 More than 112 bird species and 62 mammal species frequent the park and its wide variety of trees and shade-loving plants. About of rain falls on the forest each year. Many small tributaries of the Willamette River flow northeast through the woods to pipes or culverts under U.S. Route 30 at the edge of the park. One of them, Balch Creek, has a resident trout population, and another, Miller Creek, supports sea-run species, including salmon. Threats to the park include overuse, urban traffic, encroaching development, invasive flora, and lack of maintenance money. Occasional serious crimes and more frequent minor crimes occur in the park. ==Geology and geography== Solidified lava from Grande Ronde members of the Columbia River Basalt Group underlie Forest Park. About 16 million years ago during the Middle Miocene, the Columbia River ran through a lowland south of its modern channel. Eruptions from linear vents in eastern Oregon and Washington flowed down this channel through what later became the Willamette Valley. These flows, some of which reached the Pacific Ocean, recurred at intervals between 16.5 and 15.6 million years ago and covered almost . About eight separate Grande Ronde Basalt flows have been mapped in the Tualatin Mountains (West Hills), where they underlie the steepest slopes of Forest Park and form the columned rocks visible along Balch Creek Canyon and Northwest Cornell Road. The West Hills were later covered by wind-deposited silts that become unstable when saturated with water. Stream bank instability and siltation are common, and landslides deter urban development at higher elevations. Roughly long, the park is less than wide near downtown Portland and about wide at its northwestern end.〔 It extends along the West Hills from West Burnside Street near downtown Portland to where the Willamette River divides to flow around Sauvie Island. Covering most of the east face of the ridge above the Willamette River, it is bounded by West Burnside Street on the south, Northwest Skyline Boulevard on the west, Northwest Newberry Road on the north, and Northwest St. Helens Road (U.S. Route 30) on the east. Elevations above sea level vary from near U.S. Route 30 at the base of the ridge to about near the crest of the ridge along Northwest Skyline Boulevard. In 2008 Forest Park ranked 19th in size among the largest city parks in the United States, according to The Trust for Public Land. The trust's list included state parks, national parks, county parks, regional parks, and national wildlife refuges, as well as municipally owned parks located within cities. Chugach State Park in Anchorage, Alaska, was in first place with .〔 Portland author Marcy Houle says that the park "captures the essence of what is natural and wild and beautiful about the Northwest... From this forest sanctuary, panoramic views of the city of Portland, the Willamette and Columbia rivers, and five major peaks of the Cascade Range ... can be seen through the tall fir trees. From its inception ..., Forest Park has been a refuge for both people and wildlife, and an integral part of the environment of Portland." 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Forest Park (Portland, Oregon)」の詳細全文を読む スポンサード リンク
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