Current and Historical Trends in Use, Management and Disturbance of United States Forest Lands

These data sets present current and historical area estimates of land use, land use change, forest management, and natural disturbance for forest lands of the United States. The investigators have reconstructed portions of the history of U.S. forests of the 20th century using readily available and sometimes obscure public information collected by the U.S. Government, principally the U.S. Departments of Agriculture and Commerce. Much of the information is highly aggregated from large electronic databases containing detailed records for recent decades, and some is summarized from printed tables of information contained in hundreds of government reports from earlier decades. The quality, consistency, and available detail of the information decrease back through time.

Data sources include: USDA Forest Service, Forest Inventory and Analysis (FIA); USDA Natural Resources Conservation Service (NRCS), National Resources Inventory (NRI); USDA Economic Research Service, Census of Agriculture; U.S. Bureau of Census, Historical Statistics of the United States; and periodic reports by Agencies or special compilations requested by Congress.

Errors became evident in reconciling the different sources of information because of inconsistency in definitions, independent sampling frames, uncoordinated timing of data collection, and gaps and overlaps in scope of data collection. The investigators estimate that they are missing information on about 6 million hectares (ha) of Federal non-forest land, and that there is a double counting of about 13 million ha of private forestland and rangeland. These errors amount to about 2% of the total land area of the United States.