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Land Use Changes Involving Forestry in the United States

其他書名	1952 to 1997, with Projections to 2050
出版	U.S. Department of Agriculture, Forest Service, 2003
URL	http://books.google.com.hk/books?id=6UezzwEACAAJ&hl=&source=gbs_api

註釋About two-thirds (504 million acres) of the Nation's forests are classed as timberland, productive forests capable of producing 20 cubic feet per acre of industrial wood annually and not legally reserved from timber harvest. The USDA's 1997 National Resource Inventory shows that, nationally, 11 million acres of forest, cropland, and open space were converted to urban and other developed uses from 1992 to 1997, as the national rate of urbanization increased notably compared to the 1982-92 period. Forest land was the largest source of land converted to developed uses such as urbanization. Urban and other developed areas are projected to continue to grow substantially, in line with a projected U.S. population increase of more than 120 million people over the next 50 years, with population growth occurring the fastest in the West and South. Projected increases in population and income will, in turn, increase demands for use of land for residential, urban, transportation, and related uses. An overall net loss in forest area in the United States since the early 1950s has been due to a combination of factors, but in more recent decades has been primarily due to conversion to urban and developed uses. Total forest area in the United States is projected to decrease by approximately 23 million acres by 2050, a 3-percent reduction from the 1997 forest area. Consistent with the projected slow net decline in U.S. forestland area, private timberland area is likewise projected to decline. Total area of U.S. private timberland is projected to decline by 4 percent by 2050. Industry timberland is projected to decrease by 3.0 percent by 2050, whereas timberland area on nonindustrial private lands is projected to decrease by 4.4 percent.