NEW YORK - A single Callery-pear tree surrounded by over 400 swamp white oaks honor the memory of 9/11 as part of the September 11 Memorial Plaza being unveiled for the tenth anniversary of the New York terrorist attack. The Callery-pear, originally living near the World Trade Center, was nearly killed by the collapse of the buildings and ensuing fires, but has since recovered.

Quercus bicolor, the swamp white oaks that will surround the pear, grow rapidly and can survive 300 to 350 years, reaching 65–80 feet in height at maturity.

The 9/11 Memorial, located at the site of the former World Trade Center complex, occupies  half of the 16-acre site and features two enormous waterfalls and reflecting pools, each about an acre in size, set within the footprints of the original twin towers.

More than 400 oak trees surround two massive reflecting pools and line pathways. Swamp white oak trees were chosen to create a rustling canopy of leaves over the plaza, establishing a contemplative space. "This grove of trees bring green rebirth in the spring, provide cooling shade in the summer and show seasonal color in fall," say memorial developers.

Crews selected and harvested the trees from within a 500-mile radius of the World Trade Center site, with additional ones coming from locations in Pennsylvania and near Washington, DC , areas impacted on September 11, 2001.

Swamp white oaks, whose white oak species relatives number in the hundreds, were picked because of their durability and leaf color. In fall, the leaf color ranges from amber to a golden brown – and sometimes pink. The trees should grow as tall as 60 feet in the plaza. The trees will never be identical, growing at different heights and changing leaves at different times, a physical reminder that they are living individuals.

Pyrus calleryana, the Callery pear, is a species of pear native to China, and is related to the rose plant, rosaceae, as are other pear trees. The deciduous wood species grows up to 66 feet tall with a conical shape.