Based on schedules submitted by the director of financial management, the state treasurer shall transfer from the general fund—state, or such other funds as the state treasurer deems appropriate, to the Clarke-McNary fund such amounts as are necessary to meet unbudgeted forest firefighting expenses. All amounts borrowed under the authority of this section shall be repaid to the appropriate fund, together with interest at a rate determined by the state treasurer to be equivalent to the return on investments of the state treasury during the period the amounts are borrowed.