Illinois Forest Inventories
In 2002, a report "Forest Resources of Illinois" was published by the University of Illinois that compiled all that was known about forestland, forest landowners, and forest and wood-based businesses in the state. The report referenced earlier studies in 1998, 1996, 1985, 1962, 1948, 1924, and 1820 of forest land cover and explained how those studies were conducted as well as how that affected their accuracy. This report was a collaboration among the Illinois Forestry Development Council, the Illinois Department of Natural Resources, and the University's Department of Natural Resources and Environmental Sciences. The report was obtained from the University's Extension Forestry website and can be downloaded here (PDF 10.6 MB)
. There are many people to thank for the production of this report, including a member of the IFA board of directors. The report was authored by Scott Bretthauer and John Edgington of the University of Illinois.
The County Woodlands
page contains a table listing the forest acreage for each county from the 1998, 1985, 1924, and 1820 surveys as well as the number of forest landowners in each county as of 1996. The data in this table was excerpted from the "Forest Resources of Illinois" report.
In 1970, R. C. Anderson used the original land survey records of Illinois to create a detailed map showing the original land cover in the early 1800s, when the state was settled. This map can be seen on the Map 1820 page
Compare that to the Map 2000 page