Children from the Hill Force Base Youth Center plant a flowering plum tree April 22 in the base housing area. The base planted four trees in the housing area in conjunction with Earth Day. Earth Day, which takes place annually on April 22, serves as a day to demonstrate support for environmental protection. For Earth Day 2016, the Air Force is highlighting its commitment to cleaner, greener installations with an emphasis on energy and water conservation. (U.S. Air Force photo by Paul Holcomb)