Illinois has a program for landowners who manage unimproved ground for habitat: timber, prairie, wetland. It is run by the Illinois Department of Natural Resources. Here is how it works, and how to tell if your ground might fit. General education, not tax or legal advice. IDNR decides who qualifies, and your county assessment office applies it. This is the state program, not the federal NRCS program with the same name.
You can write it yourself or with a wildlife or forestry professional. It lays out the practices and when you will do them.
The CSP office reviews it. Staff may visit the property before approving it.
IDNR sends a certification letter, then notifies the Illinois Department of Revenue, which notifies your county assessment office.
Follow your schedule of practices for the 10 years.
Text me the county and acres. I will tell you how your ground lines up with the program and what I would put in a management plan on your place.