The future may be smaller than you think.
Forget, for a moment, the image of crystalline office buildings encircling the World Trade Center site. Until the end of this decade, there is likely to be only one skyscraper, the Freedom Tower, soaring over a low-rise retail archipelago.
As plans for ground zero assume their final form, it is more apparent than ever that what New York will get - at least in the near future - is a far cry from the renderings by Studio Daniel Libeskind that captivated and puzzled the public a year ago.
Instead of three towers along Church Street, which are to materialize eventually under the Libeskind plan, officials foresee three small buildings being constructed by 2009, with 310,500 square feet of retail space among them (about 10 percent less than the retail space in the new Time Warner Center).
They would be kin to small commercial buildings, known as "taxpayers," that generate enough income to pay the property tax bill until the market can support more ambitious development plans.
These structures would either be temporary, like the Times Square Brewery that stood briefly at Broadway and 42nd Street, or they would be permanent, ultimately serving as structural podiums for high-rise towers above, like the Hearst Magazine Building and the Newsweek Building at Eighth Avenue and 57th Street.
In any case, they would fill three large lots that might otherwise stay vacant until there is demand for 5.8 million square feet of additional office space downtown. And that could be a long time.
"We want to fill the voids," said Joseph J. Seymour, executive director of the Port Authority of New York and New Jersey. "We want to create street activity."
The authority owns the trade center site and controls the retail leasehold. It is working on the outlines of the retail program with the Jones Lang LaSalle real estate concern and Callison Architecture, after which it expects to designate an operator. "Lower Manhattan is begging for more retailing," Mr. Seymour said.
The City Planning Commission endorsed the place-holding structures on Monday, saying that the plan "under which the retail bases of all commercial buildings would be constructed prior to the tower structures themselves is a logical and feasible approach to creating a successful pedestrian environment early in the process."
Podium structures could have another benefit, in the eyes of the Lower Manhattan Development Corporation, by providing room - in double-height chambers above the three stories of retail space - for the mechanical equipment needed to serve the vast underground areas, including the PATH station and pedestrian concourses.
"This is a way of avoiding having to have 40-foot-high cooling and ventilating towers at intervals throughout the site," said Andrew Winters, a vice president of the corporation who directs planning, design and development. The roofs of the mechanical penthouses could one day serve as staging areas for the construction of the towers above, which would permit the stores below to stay open.
THOUGH two-stage, podium and-tower developments are not exactly commonplace, they have been tried before.
The monumental colonnade around the base of the Newsweek Building is the visible remnant of the three-story Colonnade Building, begun in 1922. The 21-story addition, originally occupied by General Motors, was completed five years later.
William Randolph Hearst's six-story structure of 1928, originally the International Magazine Building, had to wait far longer for its intended tower. In fact, the 36-story high-rise portion is just being constructed now, to designs by Norman Foster.
As it happens, Lord Foster is also one of three architects chosen by Larry A. Silverstein, the commercial office leaseholder at the trade center site, to design the skyscrapers that will follow Freedom Tower. So it may be that while Lord Foster is finishing one podium uptown, he will be creating a podium of his own downtown.
In broad concept, it sounds as if Mr. Silverstein endorses the idea.
"Development of first-class retail is an absolutely critical component of the World Trade Center rebuilding plan," said Janno Lieber, Mr. Silverstein's World Trade Center project director. "We would like to see it brought on line as quickly as feasible."
There are still important unanswered questions. What high-end retailer wants to lease space in a building that may well wind up as the base of a construction project, if it is not torn down altogether? Will there be enough customers before the other towers are built? Would the layout of the podium restrict the design of the office floors above?
The Civic Alliance to Rebuild Downtown New York, an umbrella organization of 27 planning, environmental, civic and other groups, criticized the development corporation on Tuesday for not providing a detailed evaluation of the low-rise interim buildings in the draft environmental impact statement, which is now out for comment.
"While reduced office density on-site may in fact be a desirable outcome," the alliance said in a 10-page report, "this scenario should be planned for and occur by design rather than by default."
Perhaps the biggest unanswered question is whether a constituency will develop over time for low-rise buildings immediately to the east of the memorial, making it that much harder politically to start building towers on those sites in the future.
But Mr. Winters does not think that will happen. "People still have an understanding in their minds of the World Trade Center site as a place of tall buildings."