Environmental Design Inc used tine-equipped diesel-powered Caterpillar wheel loaders while positioning the initial trees for the World Trade Center (WTC) Memorial grove in New York.

Each boxed tree weighs about 22,000 lb (9,900 kg).

"Forklifts were used to stage the trees," says Mark Merit, chief operating officer of Environmental Design in Tomball, Texas. "At the holding yard (in a Millstone Township, New Jersey horticultural nursery), the trees were moved from their field positions to a staging area for crane access. At the memorial site, a forklift was used to offload the tree from the freight trailer and stage the tree for crane access. We used a 988 (large wheel loader) on one end and a 972 (midsize wheel loader) on the other."

Once completed, the memorial will commemorate victims of a series of suicide attacks that the militant Islamist group al-Qaeda made upon the US on 11 September 2001, known widely as 9/11 day.

The swamp white oak "trees currently average 30 ft (9 m) in height and have a branch spread of 12 ft (3.6 m)", says Michael Frazier, senior communications manager for the 9/11 Memorial. In 2007, the trees "were chosen from areas within a 500-mile (800-km) radius of the WTC site, as well as from New York, Pennsylvania and near Washington, DC, to symbolise the locations directly impacted by the 9/11 attacks."

Environmental Design transported and planted 16 trees on 28 August and intends to plant the majority of the remaining 400 trees "between now and the 10-year anniversary" of the attacks, Merit notes. Joe Daniels, 9/11 Memorial president, oversaw the ceremonial planting of the first trees.