; (ii) on which the removal of vegetation is specifically prohibited by Federal statute; or (iii) that is included within a National Monument as of the date of the enactment of this Act. (6) Forest active management revenues The term forest active management revenues means revenues derived from the sale of national forest materials in a Forest Active Management Area. (7) National forest materials The term national forest materials has the meaning given that term in section 14(e)(1) of the National Forest Management Act of 1976 ( 16 U.S.C. 472a(e)(1) ). (8) National forest system The term National Forest System has the meaning given that term in section 11(a) of the Forest and Rangeland Renewable Resources Planning Act of 1974 ( 16 U.S.C. 1609(a) ), except that the term does not include the National Grasslands and land utilization projects designated as National Grasslands administered pursuant to the Act of July 22, 1937 ( 7 U.S.C. 1010–1012 ). (9) Secretary The term Secretary means the Secretary of Agriculture. (10) Sustained yield The term sustained yield means the maximum annual growth potential of a forest calculated on the basis of the culmination of mean annual increment using cubic measurement. (11) State The term State includes the Commonwealth of Puerto Rico. (12) 25-percent payment The term 25-percent payment means the payment to States required by the sixth paragraph under the heading of FOREST SERVICE in the Act of May 23, 1908 (35 Stat. 260; 16 U.S.C. 500 ), and section 13 of the Act of March 1, 1911 (36 Stat. 963