Snapshot: Tree City USA: 25 years running Published May 1, 2017 By Senior Airman Zachary Cacicia 436th Airlift Wing Public Affairs DOVER AIR FORCE BASE, Del. -- Sen. Tom Carper, Del., speaks at the State of Delaware Arbor Day event April 28, 2017, at Dover Air Force Base, Del. The event recognized Dover AFB as a Tree City USA for 25-straight years. (U.S. Air Force photo by Senior Airman Zachary Cacicia)