The Boston Public Schools will cut tens of millions of dollars in spending for the next school year as the city continues to confront revenue woes, according to a preliminary budget Superintendent Carol R. Johnson presented to the School Committee last night.
The proposal, which follows two years of intense budget chopping, calls for such incremental measures as freezing administrative salaries, turning down heat in schools and offices, and reducing custodial staff.
But the cuts could go much deeper as the department considers an array of other potentially controversial options in the coming weeks, as it reduces spending by $57.7 million. Under consideration: school closings, reduced busing, furlough days, wage freezes, or pay cuts.
“Our intent is not to scare people,’’ John McDonough, the school system’s chief financial officer, said in an interview before the meeting. “Our intent is to provide a realistic view of the scope of challenges we face.
The Boston public schools do not “operate in isolation of the larger economic climate,’’ he said. “At the end of the day, we will find a pathway to success that will put us in a stronger position in the long term.’’
The superintendent’s budget proposal of $809.7 million complies with a request by Mayor Thomas M. Menino to reduce next year’s spending plan by 1 percent from this year, a rate much lower than the mayor’s orders for other city departments.
While that amount represents $8.2 million, the district must cut far more to compensate for the rising costs of doing business, such as covering contractually negotiated pay increases and health insurance costs.
The tough decisions reflect similar conversations unfolding in city halls and town offices across the state, as Massachusetts struggles to recover from the recession and even as Governor Deval Patrick vows not to cut aid to schools next year.
Earlier this week in Arlington, more than 100 students urged selectmen to ask voters to support a hefty property tax increase to avoid teacher layoffs.
Last night in Boston, where no teacher layoffs are planned, only a few dozen people showed up for the meeting at the School Department’s downtown headquarters. That contrasted sharply with last year, when a student march preceded the meeting and hordes of people packed the chamber holding signs advocating for preservation of teaching positions and the arts, as district officials predicted the loss of more than 900 administrative, teaching, and other jobs.
McDonough, in presenting the superintendent’s budget last night, stressed that closing schools was merely an option to explore, but he pointed out that it could save the district millions of dollars. He said the system has roughly 4,500 empty classroom seats, each costing the district $4,000, and excess capacity is expected to grow as the state opens more independently run charter schools.
Boston could potentially be running an inefficient system, McDonough said. The average enrollment of a Boston school is 450, while dozens of schools have fewer than 250 students, he said. By contrast, the average school size among the nation’s 100 largest districts is 750 students, he said. McDonough also said that school districts about the size of Boston on average have 76 schools; Boston has 135. He said his office will be doing a more thorough inventory of the district’s excess capacity.
“We are talking millions of dollars that could be reinvested,’’ McDonough said.
That money, he said, could help the superintendent pay for educational improvements. Johnson is planning dramatic changes at 14 underperforming schools and spending an additional $10 million next year to bring programs for students learning to speak English into compliance with state and federal laws.
Boston shuttered six school buildings at the end of last year, prompting scores of protests, but it also decided to expand a few schools.
Johnson has been reluctant to pursue additional school closings. As recently as last week, she told the Globe that she was unsure if she would close any schools as she opens three city-run charter schools, hoping to lure more students back to the district.
Several School Committee members, who will be voting on the proposal next month, asked about or commented on the excess capacity.
“If [the city] is going to shut down schools, you need to make it clear to students that you are not shutting down their hope,’’ said Michael Davis, the committee’s student representative. “Closing schools can be traumatizing to students.’’
After the meeting, Samuel Tyler, president of the Boston Municipal Research Bureau, said school closings appear inevitable. “There’s a lot of hard choices,’’ said Tyler. “Certainly excess capacity - you can’t ignore that.’’
James Vaznis can be reached at jvaznis@globe.com. 
