New York, NY (September 12, 2013) – The National September 11 Memorial includes two reflecting pools in the footprints of the World Trade Center’s twin towers, inscriptions of the names of the people who died at the site, and a beautiful collection of 412 trees. Designers of the memorial believe in the importance of the trees both to the people who work and live in the area today and to visitors who come to pay respects to the fallen. They’ve taken every precaution to ensure the trees will thrive.
The swamp white oak trees, which surround the reflecting pools, or “voids,” are spaced so that as they reach their expected mature height of 60 feet, their crowns will knit together to form a dense overstory sheltering the entire plaza, except for the voids, which will remain open to the sky.
The city trees will have to contend with a variety of challenges, including air pollution and high temperatures caused by the urban “heat-island” effect. Paved surfaces also lessen rainfall reaching a street tree’s roots.
Some tree species adapt better than others to urban conditions. Swamp white oak, or Quercus bicolor—native to the Midwest, parts of the Mid-Atlantic and southern New England—is one of them. This pest- and disease-resistant tree tolerates dry, moist or wet soils, as well as salt, soil compaction and buffeting winds. It is also easier to transplant than other oak species because it does not have a taproot. All of these factors made swamp white oak a prime candidate for the 9/11 Memorial. It’s an attractive, solid tree, with deep green summer leaves, yellow fall foliage and a rounded canopy.
Bartlett Tree Experts was selected to raise the trees, and they have contracted to care for transplanted trees at the memorial site for at least the next two years. Bartlett grew the trees in large containers for five years at one of their New Jersey locations, so that they could be transplanted with their entire root system in tact, avoiding typical transplant stress. Read more in Horticulture Magazine.
Source: “9-11 Memorial Trees,” Horticulture Magazine