(2) Report Not later than 4 years after the date of the enactment of this Act, the Secretary of the Interior shall submit a report to Congress on the results of the study conducted under this subsection. (d) Conforming amendment The table of sections for subpart B of part IV of subchapter A of chapter 1 of such Code is amended by adding at the end the following new item: 30E. National Scenic Trail conservation credit. . (e) Effective date The amendments made by this section shall apply to contributions made after the date of the enactment of this Act.