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Deforestation in the United States
Deforestation in the United States is an ongoing environmental issue that attracts protests from environmentalists. Prior to the arrival of European-Americans, about one half of the United States land area was forest, about in 1600, yet today it is only about .〔(Forest Resources of the United States )〕 Nearly all of this deforestation took place prior to 1910, and the forest resources of the United States have remained relatively constant through the entire 20th century.〔
The 2005 Food and Agriculture Organization (FAO) ''Global Forest Resources Assessment'' ranked the United States as seventh highest country losing its old growth forests, a vast majority of which were removed prior to the 20th century.〔
==After European colonization==
For the 300 years following the arrival of Europeans, land was cleared, mostly for agriculture, at a rate that matched the rate of population growth.〔('Collapse': How Societies choose to Fail or Succeed ), The New York Times〕 For every person added to the population, one to two hectares of land was cultivated.〔American Forest A History of Resiliency and Recovery United States Forest Service〕 This trend continued until the 1920s when the amount of crop land stabilized in spite of continued population growth. As abandoned farm land reverted to forest the amount of forest land increased from 1952 reaching a peak in 1963 of . Since 1963 there has been a steady decrease of forest area with the exception of some gains from 1997. Gains in forest land have resulted from conversions from crop land and pastures at a higher rate than loss of forest to development. Because urban development is expected to continue, an estimated of forest land is projected be lost by 2050,〔(Land Use Changes Involving Forestry in the United States: 1952 to 1997, With Projections to 2050 )〕 a 3% reduction from 1997. Other qualitative issues have been identified such as the continued loss of old-growth forest,〔United Nations (2005) "Global Forest Resources Assessment"〕 the increased fragmentation of forest lands, and the increased urbanization of forest land.〔U.S. Department of Agriculture "Forests on the Edge - Housing Development on America's Private Forests" (2005) http://www.fs.fed.us/projects/fote/reports/fote-6-9-05.pdf Retrieved November 19, 2006〕
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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