Joint Base Andrews Youth Center children carry small trees to be planted in the behind the Youth Center woods in celebration of Earth Day on Joint Base Andrews, Md., April 22, 2013. In one year, an acre of trees can absorb as much carbon as is produced by a car driven up to 8,700 miles according to the International Society of Arboriculture. (U.S. Air Force photo/Airman 1st Class Nesha Humes)