No private property shall be acquired by eminent domain hereunder until and unless the state park board or governing body of such county or city shall adopt a resolution or formal order declaring the public purpose or use therefor or shall have adopted a plan for conservation of open spaces embracing such property, and shall have held a public hearing thereon, and received the report of the planning agency of the state or county or city with regard to such acquisition.
§ 67.885, RSMo