Susan Bench-Snow, Secretary of the Air Force Administrative Assistant Facilities director, shows Under Secretary of the Air Force Erin Conaton the ?green? roof of the William A. Jones III Building following an Earth Day and Arbor Day tree planting ceremony at Joint Base Andrews, Md., April 20, 2011. The roof of the Jones Building is lined with low maintenance flora, which will not exceed more than eight inches in height and keeps the building cooler in the warmer months while using less energy. (U.S. Air Force photo/ Senior Airman Melissa V. Brownstein)