Mich. Comp. Laws § 209.152
The powers and duties now vested by law in the board of state tax commissioners are hereby transferred to and vested in the state tax department, and all records, files, books and papers of every nature pertaining to the functions of said board shall be turned over to said state tax department and shall be preserved as a part of the records and files of said department. Upon the taking effect of this act, the board of state tax commissioners shall be abolished, and the powers and duties heretofore exercised and performed by said board, under authority of law, shall hereafter be exercised and performed by the state tax department. Whenever, in any law of the state, reference is made to the board of state tax commissioners, whose powers and duties are thus transferred, such reference shall be deemed to be made to the state tax department.
MCL 209.152