As used in this Division:
"Unimproved land" means woodlands, prairie, wetlands, or other vacant and undeveloped land that is not used for any residential or commercial purpose that materially disturbs the land.
"Conservation management plan" means a plan approved by the Department of Natural Resources that specifies conservation and management practices, including uses that will be conducted to preserve and restore unimproved land.
"Managed land" means unimproved land of 5 contiguous acres or more that is subject to a conservation management plan.
35 ILCS 200/10-405