Airmen line up and stack Christmas trees along the fence during the Trees for Troops event on Ellsworth Air Force Base, S.D., Dec. 1, 2011. More than 300 trees were donated for the Ellsworth Airmen and their families. Spouses of deployed Airmen were able to pick out a tree the first day and the remaining trees were available to all other Airmen on a first-come, first-served basis.(U.S. Air Force photo by Airman Alystria Maurer/Released)