area vocational centers and special education cooperatives may be formed by joint agreement between two or more school districts. a board consisting of representatives of each participating school district governs each entity of these two types. educational service regions replaced the former county school units administered by county superintendents. each region originally served one county but now may serve multiple counties because of minimum population requirements. each region is headed by a regional superintendent of schools and is also governed by a regional board of trustees; the latter deal primarily with district boundary changes. township land commissioners manage school lands and funds in certain counties. educational service centers are established by the state board of education and function primarily to coordinate and provide special and ordinary services to affiliated school districts. these service centers are governed by boards consisting of members appointed by the regional superintendent.