The first of a series of confrontations between supporters and opponents of the cap placed on Prince George's County real estate tax revenues occurred last night in Hyattsville, where more than 30 civic activists gathered for a spirited debate.

The forum was the first debate scheduled between the supporters of TRIM (Tax Reform Initiative by Marylanders), the tax-limiting charter amendment approved by county voters five years ago, and its opponents, who have adopted the acronym FACT (Fairness for All County Taxpayers) and favor modifying it.

A new county charter amendment that will appear on the November election ballot would freeze the county's real estate tax rate at $2.40 per $100 assessed value instead of limiting to $144 million the dollar amount that can be collected in property taxes annually.

Robert Ostrom, an Upper Marlboro lawyer and former county attorney, had the harder time of it last night as the overwhelmingly pro-TRIM crowd questioned him about the need for the amendment, which county officials say could allow them to raise $6 million to $8 million in critically needed new revenues next year.

"The question on the ballot doesn't do away with TRIM," Ostrom said. "It puts TRIM in some perspective. It provides for flexibility and at the same time is a tax limitation."

Jack Gleason, who spoke for the pro-TRIM forces, came to the meeting equipped with charts and props. The county, he said, is relatively wealthy and does not need the extra money that the amendment would provide.

Items such as the county's Public Works Department budget have decreased since TRIM passed in 1979, he said, because of "a decision by county government on what to prioritize.

"You're going to hear that if you don't support the TRIM amendment that your house is going to burn down," Gleason said as several in the audience nodded their approval. "Let me assure you. No fire calls go unanswered."

The county's real problem, Gleason insisted, comes in its mismanagement of the funds it already receives.

Ostrom countered that the question of fiscal management is a separate issue in the TRIM debate. "Be very careful of some of the numbers you see there," he said of Gleason's charts.

But Ed Heuer of Seabrook questioned Gleason's flurry of figures.

"After a while I began to feel I was seeing shells moved around on a table," Heuer said. "The question still is: How should I vote? Either way there are other ramifications and implications down the line."

The next forum will be held at 7:30 p.m. Tuesday at the Maryland-National Capital Park and Planning Commission office in Riverdale.