The Forest Service, U.S. Department of Agriculture's (USDA's) Northern Research Station Forest Inventory and Analysis program (NRS-FIA) uses digital land cover products derived from remotely sensed imagery, such as the National Land Cover Dataset (NLCD), for the purpose of variance reduction via postsampling stratification. The update cycle of the NLCD product is infrequent; NLCD 2001 was the first update since the release of NLCD 1992, and was not yet fully completed as of late 2006. Consequently, FIA field data collected as recently as 2005 are being poststratified with land cover data collected more than a decade before. In addition, NRS-FIA has performed its own land cover classification of remotely sensed imagery for use in the stratification of some States, a time-consuming process. Alternative sources of information need to be evaluated both to eliminate the temporal mismatch between land cover data and FIA plot information and to reduce the amount of analyst time required to perform the stratification process.
Liknes, Greg C.; Nelson, Mark D.; Gormanson, Dale D.; Hansen, Mark. 2009. The utility of the cropland data layer for Forest Inventory and Analysis. In: McRoberts, Ronald E.; Reams, Gregory A.; Van Deusen, Paul C.; McWilliams, William H., eds. Proceedings of the eighth annual forest inventory and analysis symposium; 2006 October 16-19; Monterey, CA. Gen. Tech. Report WO-79. Washington, DC: U.S. Department of Agriculture, Forest Service. 259-264.