35 ILCS 200/10-420

(a) In all counties, except for Cook County, beginning with assessments made in 2008 and thereafter, managed land for which an application has been approved under Section 10-415 that contains 5 or more contiguous acres is valued at 5% of its fair cash value. (b) The special valuation under this Section does not apply to (i) any land that has been assessed as farmland under Sections 10-110 through 10-145, (ii) land valued under Section 10-152 or 10-153, (iii) land valued as open space under Section 10-155, (iv) land certified under Section 10-167, or (v) any property dedicated as a nature preserve or a nature preserve buffer under the Illinois Natural Areas Preservation Act and assessed in accordance with subsection (e) of Section 9-145.