; and (B) the Secretary of Agriculture. (3) Secretary concerned The term Secretary concerned means— (A) the Secretary of the Interior, with respect to activities under the Department of the Interior; and (B) the Secretary of Agriculture, with respect to activities under the Department of Agriculture. (4) Wildfire The term wildfire means any nonstructure fire, other than a prescribed fire, occurring in vegetation or natural fuels on— (A) public land; or (B) National Forest System land created from the public domain. (5) Wildland-urban interface (A) In general The term wildland-urban interface has the meaning given the term in section 101 of the Healthy Forests Restoration Act of 2003 ( 16 U.S.C. 6511 ). (B) Exclusion The term wildland-urban interface does not include— (i) any forest reserve not created from the public domain; or (ii) any national grassland or land utilization project administered under title III of the Bankhead-Jones Farm Tenant Act ( 7 U.S.C. 1010 et seq.). 4. Unmanned aircraft systems (a) Definitions In this section: (1) Restricted airspace The term restricted airspace means an area for which the Administrator of the Federal Aviation Administration has established a temporary flight restriction for a wildland fire. (2) Unmanned aircraft; unmanned aircraft system The terms unmanned aircraft and unmanned aircraft system have the meaning given those terms in section 331 of the FAA Modernization and Reform Act of 2012 ( Public Law 112–95