NEW YORK (AP) - After nearly nine years, life is returning to ground zero in a tangible way.
      
Crews on Saturday morning began planting 16 swamp white oak trees around the eight-acre plaza, which will serve as a memorial to the nearly 2,800 people killed in the terror attacks of Sept 11,  2001.
      
The trees are the first of more than 400 that will line the plaza, creating an overhead canopy for visitors.
      
The 16 trees were cultivated for four years on a New Jersey nursery and loaded into eight tractor-trailers at midnight Friday for the 35-mile trip to Manhattan.
      
The trees will eventually soar to 80 feet. Memorial planners said swamp white oaks were chosen for their durability and because they grow naturally in the New York area, Washington and Pennsylvania, where the terror attacks took place.