California reduced its number of underprepared teachers last year, but that was the sole bit of good news in a report to be released today that paints a dismal picture of the state's future supply of qualified educators.

As students face more rigorous academic standards, a looming wave of retirements means California could soon be facing another teacher shortage, the Center for the Future of Teaching and Learning found.

"This is the sound of the bell ringing here," said Margaret Gaston, director of the center that analyzes state data and research by SRI International to produce the annual report.

Modesto City Schools, for one, is bracing for a surge in retirements in the next four to five years, said Barney Hale, executive director of the Modesto Teachers Association, which represents about 1,800 teachers.

Without any incentive, 43 teachers retired last year, compared with 25 to 30 retirees in a typical year, Hale said. Projections show that the number of teachers retiring will rise to 60 this year and peak at 90, Hale said. Teachers are also retiring younger — last year the average age was 61.

Between the rise in retirees and the escalating cost of living and flattened salaries, local school districts will struggle to hire young people who want to stay in the Bay Area, Hale said.

"The lure of this community was the cost of living was lower, and you can afford to buy a house," he said.

The enrollment in elementary school is declining, so retirements may help avoid layoffs. But the number of older kids is growing, so the struggle to hire special education, math and science teachers will intensify. Hale said the city schools may have to offer extra money to those teachers, as other districts have.

There are also many high school educators teaching subjects that they are not trained to teach, said Gaston, the center director.

As a result, 20 percent of English, math and social science teachers, as well as 32 percent of physical science teachers, were either underprepared or teaching out of their field, researchers found.

That's worrisome because high school seniors will be required to pass a high school exit exam to get a diploma starting next year, Gaston said.

Middle school teachers are also tougher to find than pri-mary level teachers, said David Holtz, assistant superintendent of human resources for the Sylvan Union Elementary School District in northeast Modesto.

So far, early recruitment has helped draw enough high-quality middle school candidates, but Holtz said more and more district officials are asking professors at teacher colleges for referrals, after postings fail to yield enough responses.

The report's silver lining was that California has reduced the number of underprepared teachers to 28,000 — about 9 percent of the work force — during the last school year. Three years earlier, 42,500 teachers, or 14 percent, were classified as underprepared. The center defines an underprepared teacher as one in an intern or pre-intern program, or one working on an emergency permit or waiver.

In schools that serve large numbers of poor or minority students, the numbers are much higher, Gaston said.

"If you look at minority students in California, they are five times more likely to have an underprepared teacher," she said.

"We still have some real disparity there."

On the Net: The Center for the Future of Teaching and Learning: www.cftl.org. Bee staff writer Elizabeth Johnson contributed to this report.