The Metropolitan District Commission will begin cutting down 13 maple trees today along Memorial Drive to make way for the construction of a sewer.

John W. Sears '52, chairman of the MDC, said yesterday "we can no longer hold the axes up. The contracts have already been signed and we've got to begin work if we are going to finish the project on time."

The MDC will replace the maples with 18-foot tall sycamore trees as soon as the project is completed. The sewage pipe will intercept mixed sewage and storm water now discharged into the Charles River and divert it to the MDC's Deer Island treatment plant.

Sears said yesterday that the decision to cut down the maple trees followed a series of meetings with a Cambridge citizens group headed by City Councillor Robert Moncreiff.

"I know of no complaints about our decision to cut down the trees. Originally, there was some controversy over placement of the new sycamores, but we deferred to the wishes of Professor (Charles W.) Eliot (professor emeritus of the Graduate School of Design) on that score," Sears said.

'Acquiesce'

Moncreiff said last night that the people of Cambridge were forced to "reluctantly acquiesce" to the MDC's decision.

Moncreiff said that his committee began mobilizing support against the tree removal when "it was too late to do anything about it." He said he had been assured by Sears that in the second phase of the project--which will bring the sewer's pipe line up as far as Lowell St. at the Mt. Auburn Street Hospital--"the community will be consulted at every juncture."

Sears said yesterday that the second phase of the project might dictate the removal of an additional three or four trees.

Robert B. Sturgis '44, president of the Boston Society of Architecture and an organizer of a number of protests against the tree removal, said yesterday that he was satisfied with Sears's proposal.

"In a couple of years the area will look the same as it does now, but the original issue remains," Sturgis said.

The issue Sturgis referred to was a 1964 MDC plan to build three underpasses under Memorial Drive to ease traffic congestion. Opponents of the plan argued that its implementation would turn Memorial Drive into a superhighway. The MDC dropped the proposal following community protests.

Sears said yesterday that he would probably be called before a joint legislative committee in the next month and be questioned why the underpasses--which the legislature authorized in 1962--had not been constructed. He said he would resist efforts to revive the 1964 plan.

Magdalena Finley, wife of John H. Finley, Eliot Professor of Greek Literature and former Master of Eliot House, said yesterday that "while some of the maples along Memorial Drive are sort of sad, it is a shame that they have to cut down some of the healthier looking ones by Winthrop House.