Two members of the Montgomery County School Board last night sharply criticized the county's master plan for closing schools, calling it shortsighted and risky at best.

But the school board, in its first vote on the controversial plan, decided to close two high schools. Robert E. Peary High will close in June of 1983, or as soon as feasible, and Northwood High will close a year later. A total of 31 schools are up for closing as the board votes this month.

Before last night's voting, however, board member Joseph R. Barse, usually aligned with the board's conservative majority, complained that projected enrollment forecasts contained in the 15-year school plan were "uncertain" and he said there is no "safety margin" over the long term if those projections prove inaccurate.

Barse said the plan also failed to consider "the role of schools as the fabric of a community." Instead, he charged, the plan treated schools merely "as facilities" detached from the communities they serve. The plan should have taken into account the presence of day-care centers in assessing whether a school should close, Barse added.

Meanwhile, board member Blair Ewing, a dissenting liberal, said the school-closing process was "badly flawed."

"I am not sanguine that what will be done will be well and fairly done," Ewing said. He said the board had omitted from its deliberations the important goal of maintaining racial balance and that board statements regarding racial issues had made "a mockery of any real commitment to that objective."

But the majority of board members, while emphasizing the difficulty of choosing schools for closing, stressed the need to go ahead with the decisions on budgetary grounds. "We're trading off buildings for programs," said Eleanor Zappone, summing the feeling of many of her colleagues. "Empty seats and empty classrooms cost money."

The decision to close Peary was no surprise, but the plan originally called for closure in 1986. The board amended that last night after some community insistence that the school should not have to undergo a "lengthly withdrawal period."

The Northwood closure was rife with controversy from the start. The issue was really over whether to close that school or neighboring Einstein High, and the debate centered largely on which school would be more costly to renovate and when renovations would be necessary.

The final vote was 5 to 2 in favor of closing Northwood, with Barse and Board President Carol F. Wallace voting against shutting down the school. Barse has insisted all along as a matter of principle that no senior high schools should be closed.

Wallace, anticipating what is likely to be public outcry over the board's decisions on school closings, said at the outset that members' judgments were "rendered in the spirit of public service." Then she urged communities to come together once the decisions were made.