Appropriations for the work of the Forest Service available for the operation, repair, maintenance, and replacement of motor and other equipment may be reimbursed for use of such equipment on projects of the Forest Service chargeable to other appropriations, or on work of other Federal agencies, when requested by such agencies, reimbursement to be made from appropriations applicable to the work on which used at rental rates fixed by the Chief Forester based on the actual or estimated cost of operation, repair, maintenance, depreciation, and equipment management control, and credited to appropriations currently available at the time adjustment is effected. The Forest Service may also rent equipment for fire-control purposes to State, county, private, or other non-Federal agencies cooperating with the Forest Service in fire control under the terms of written cooperative agreements, the amount collected for such rental to be credited to appropriations currently available at the time payment is received.