Mich. Comp. Laws § 458.46

Sec. 6. The secular affairs of such church shall be managed by a board of trustees, consisting of not less than 3 nor more than 9 members, to be elected by ballot by said corporation from the membership of the church. The said trustees shall hold office for such term as the said church shall decide upon, and until their successors are elected, unless they cease to be members of said church, in which case they shall also cease to be trustees. Vacancies in said board may be filled at any time for the balance of the term, by an election as in other cases.