Trees lower energy costs, shade residents from the sun’s ultraviolet rays, mitigate stormwater run-off, and increase property values. Trees are a great addition to a building’s entrance, courtyard or backyard. Street trees beautify New York City and clean our air. They need 20 gallons of water a week during hot weather, and must be protected. You can get “curb your dog” signs, and protective pit guards to keep bikes, cars, and pedestrians from hurting trees at: