The crescent of trees has now been expanded into a rough circle that surrounds the bowl-shaped piece of land where United Airlines Flight 93 crashed on Sept. 11, 2001.
After the winning design was announced on Sept. 7 in Washington, D.C., critics questioned why the crescent shape would be used when that symbol is often associated with Islam, the religion of the men who hijacked and crashed the plane.
Though the concept of an embracing gesture of the landscape remains, the crescent shape is gone.
"We're enthusiastic in the developments," said Paul Murdoch, the project's designer, in announcing the design changes today. "We think the entry is stronger now."
Visitors will walk through a small portal through the trees to a plaza that will look out onto the "sacred ground," which is the resting place of the 40 passengers and crew members who died.
"The focus of that bowl is the impact site," Mr. Murdoch said.
Mr. Murdoch believes the change to the crescent would have been made despite the public outcry connecting it with Islam.
"These enhancements, if in any way we thought they were a compromise, we would not be putting them forward," he said. "The variety of visitor experience is more enriched, I think, than it was before."
Besides focusing more attention on the actual impact site, the added trees will also serve as a buffer to block adjoining properties.
"I think what we want to do is move beyond any kind of divisive labeling and really focus on the experience of this memorial," Mr. Murdoch said.
Project organizers hope the memorial is completed by the 10th anniversary of the crash.
