RESTON, Va., April 12 (UPI) — A U.S. government study says forest cover over the eastern United States is again declining after increasing during much of the 20th century.
The study led by Mark Drummond and Thomas Loveland of the U.S. Geological Survey, examined changes in the eastern part of the country from 1973 to 2000 using remotely sensed imagery as well as statistical data, field notes and ground photographs.
The researchers said they found a 4.1 percent decline in total forest area, a “substantial and sustained net loss” equivalent to more than 3.7 million hectares. The researchers describe considerable regional variation, with net loss being particularly marked in the southeastern plains.
They said the net loss occurred although reforestation of abandoned fields and pastures continued in some regions more than others. Most net forest loss, they said, occurred as a result of timber production, which keeps some land free of forest, and as a result of urban expansion, which is generally a permanent change.
Mountaintop removal for mining in the Appalachian highlands has also had a “substantial impact” on eastern land cover, they said, contributing more than 420,000 hectares of net forest decline.
The study appears in the April issue of the journal BioScience.
Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.