70 ILCS 805/6e
The board of a forest preserve district located in a county that has a population of no more than 550,000 may sell any one or more parcels of land owned by the district that are less than one acre in size whenever the board determines the sale to be advantageous to the district. The board shall approve the sale by a two-thirds vote of the members of the board then holding office. A sale may not be approved by the board unless all parcels of land involved in the sale have been appraised by an MAI appraiser or a State-certified real estate appraiser within one year before the date the sale is to take effect. The net proceeds of the sale of any parcel of land under this Section shall be set aside for the district's future land acquisitions and may not be utilized for any other purpose.
70 ILCS 805/6e