Defying both economic headwinds and local critics, the University has begun clearing space for the 13th and 14th residential colleges.

A woodchipper growled as work crews uprooted trees around 70 Sachem St. on Tuesday, on the corner of the Prospect Triangle, the future site of the new residential colleges. A trash chute extended from a second-story window of Brewster Hall, and the whole area, except Mudd Library and Donaldson Commons, has been fenced off by blue tarp.

Associate Vice President for New Haven and State Affairs Michael Morand ’87 DIV ’93 said the removal of buildings began a few weeks ago.

“The work is being done carefully, as we are both salvaging as much of the worthy architectural elements as possible and recycling the bulk of the building material,” Morand said in an e-mail.

Deputy Provost Lloyd Suttle said the unoccupied buildings on the site are scheduled to come down this fall, although he was not aware of how the demolition is progressing. Although construction of the colleges, originally planned to open 2013, has been delayed because of the recession, the project is proceeding as long as gift funding is available. And, Suttle said, there is already enough funding for the demolition.

Yale received permits on Sept. 4 to demolish 70 Sachem St. and two other buildings.

In recent months, groups such as the New Haven Preservation Trust and the Connecticut Trust for Historic Preservation have pleaded with Yale to save seven historic buildings, including Hammond Hall, Brewster Hall, the Daniel Cady Eaton House and two houses on Prospect Street, as well as the Seeley G. Mudd Library. But the University has shown every intention of pressing forward with its plans.

Told of Tuesday’s activity at the site, Anstress Farwell GRD ’78, president of New Haven Urban Design League, said, “There’s nothing new to say. It’s just wrong. They’re throwing away buildings that have life in them and have importance.”

The University studied options for preserving Hammond Hall and incorporating it into the design of the new colleges but ultimately decided against it.

“We, the University, studied all the buildings on the site and made this decision in order to have the new colleges be comparable to the renovated colleges currently on campus,” School of Architecture Dean Robert A.M. Stern ARC ’65, whose firm is designing the colleges, said in a recent interview. “This is a highly charged, politicized issue.”

Paul Needham, Victor Zapana and Baobao Zhang contributed reporting.