Estimating and Circumventing the Effects of Perturbing and Swapping Inventory Plot Locations.

This article focuses on the functions of the Forest Inventory and Analysis (FIA) program of the U.S. Department of Agriculture Forest Service. The FIA program conducts comprehensive forest inventories of the U.S. to estimate the area of forestland. Traditionally, it has reported estimates of forest attributes for states and counties. Increasingly, however, users request plot data for estimation for their own areas of interest. But, the FIA program is constrained by law from disclosing exact locations and, instead, releases only approximate locations. To comply with the Freedom of Information Act of 1966, FIA plot locations on private lands made available to the public are perturbed, the locations of some plots are swapped with those of similar plots, and private ownership information is masked.