Historically, the North Central Research Station's Forest Inventory and Analysis (NCFIA) program conducted inventories of a State's forests on a periodic basis. In Illinois, periodic inventories were completed in 1948, 1962, 1985, and 1998 (Essex and Gansner 1965, Raile and Leatherberry 1988, Schmidt et al. 2000, USDA FS 1949). In 2001, NCFIA began fieldwork for the fifth inventory of Illinois' forest resources.