Mich. Comp. Laws § 458.86

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 said corporation from the membership of the church, the said trustees to hold their office for the term of 1 year. Vacancies in said board may be filled at any time for the balance of the term, by an election as in other cases.