New York ? The memorial honoring World Trade Center victims will include a forest of oak trees with a clearing for Sept. 11 gatherings and a Memorial Hall between the twin reflecting pools that will mark the footprints of the lost towers, officials announced Thursday.

Among the new elements of the site released Thursday were the Memorial Hall, a 1.5-acre clearing at ground level for public gatherings, and the exposed stumps of columns that supported the twin towers.

John Whitehead, chairman of the Lower Manhattan Development Corp., the agency overseeing rebuilding, called Memorial Hall a new public space where visitors will be able to “review a directory of the names, locating their loved ones among the souls that are there.”

Gov. George Pataki, Mayor Michael Bloomberg, victims’ family members and designers of the site also attended a news conference to release details of the memorial design.

“We have to have a memorial that really allows us to connect the sheer enormity of the twin towers to the individuals that were taken from us,” Bloomberg said, “and I guess to the higher powers in whose hands we really place our fragile lives every day.”

Michael Arad’s design, “Reflecting Absence,” was chosen earlier this year out of more than 5,000 submissions from around the world.

Architects Michael Arad, left, Peter Walker, center, and Max Bond discuss their design for a memorial at the World Trade Center site during a news conference in New York. The new schematic design features a landscaped civic plaza, deeply recessed pools and an area for those lost but never identified.

In keeping with architect Daniel Libeskind’s overall site plan, there will be access to the stumps of columns that held up the twin towers and to the slurry wall that prevented the Hudson River from flooding the site.

“These cut-off columns, this foundation slab, this slurry wall, all together form part of the literal story of survival of that day,” Arad said. “These are artifacts that one can touch, and sense the past through them, and register the brutality of these events.”