((a)) ** Authorization of appropriations** Except as provided in subsection (b), there are authorized to be appropriated—

((1)) an amount not to exceed 5 percent of the sum of—

((A)) the sums received by the Secretary from sales of timber and other products of the forests; and

((B)) user fees paid in connection with the use of forest lands; and

((2)) such additional sums as may be necessary to carry out the purposes of this subchapter.

((b)) ** Limitation on authorization** Subsection (a) shall not in any way affect payments to the States pursuant to .section 500 of title 16

((c)) ** Spending authority** Any spending authority (as defined in ) provided in this subchapter shall be effective for any fiscal year only to such extent or in such amounts as are provided in appropriation Acts.section 651 of title 2