Since environmental problems arise largely from the way land is used, traditional land-use policy has come under challenge. Zoning regulations are one example of legal limitations on land use. Another is the common-law concept of nuisance, which places limits and responsibilities on the rights of ownership. On such grounds, pressure for land-use reform has sharply intensified since the 1960s. It is argued that as accessible land grows scarcer, its function becomes more critical, therefore choice of that function should no longer be dictated by private profit or local convenience. Moreover, local laws and zoning regulations are inadequate for settling land-use questions involving regions that cut across local boundaries, such as wetlands, shorelines, and floodplains, or large-scale facilities such as strip mines, sewer systems, power plants, and highways. As a consequence, environmentalists have gone to court to prevent or resite the construction of projects that would degrade the environment. Land-use court battles have been waged over the siting of jetports, petroleum refineries, offshore tanker depots and drilling rigs, nuclear power stations, high-voltage transmission lines, dams, and even shopping centers and housing developments. The U.S. Dept. of Agriculture (USDA), in its periodic inventory of natural resources, reported in 1999 that during the five-year period from 1992 to 1997 the nation's privately held forests, croplands, and wetlands were lost to development in and around cities and towns at twice the rate they were from 1982 to 1992.
The land-use policy of such public lands as the U.S. national parks and forests is a matter of continuing controversy. Under the control of the USDA, the policy is to protect the environment while permitting some commercial exploitation of renewable resources. Critics charge that the encouragement of tourism overutilizes already fragile ecological systems and that the USDA favors timber companies over preservation of old-growth forests. In the early 1990s the issue was starkly illustrated by the spotted owl, a threatened species whose habitat in old-growth forests under federal supervision was threatened by timber-cutting policies. One possible solution is to create a biosphere reserve, which provides a core area in which no disturbance to the ecosystem is permitted, a transition area in which experimental research is allowed, and a buffer zone that protects the biosphere from external development pressures.