The future of a large upscale development near Upper Marlboro has been thrown in doubt by new Prince George's County Planning Board data released this week showing overcrowding at a local high school that would serve the new homes.

Even without the new homes, crowding is expected to worsen at Frederick Douglass High School, the new data show. That information led the county Planning Board on Thursday to say that the Beech Tree development, along with several other smaller developments, is stalled.

Beech Tree, which is to include 2,400 homes and a Greg Norman-designed golf course, had survived legal challenges by local anti-growth activists, and its developers were prepared to begin work on the first 130 lots.

But the Planning Board decision this week means that no homes can be built at Beech Tree until the school situation is resolved, said William J. Anthony, Washington development director for Ryko, a Houston corporation that owns the 1,200-acre tract off Route 301. The company planned to sell quarter-acre lots without houses for $75,000 each, he said.

"My only comment is that overall, the county has the capacity in the high schools," Anthony said. "You've got to scratch your head [about] what's going on here. The numbers all seem to be shifting."

The golf course is not directly affected by the Planning Board's decision.

The local elementary school is also crowded, but County Executive Wayne K. Curry (D) won County Council support last year to speed up funding for a new elementary school that would serve Beech Tree.

Douglass is at 135 percent of capacity. Under Planning Board rules, no subdivision may proceed if schools exceed 130 percent of capacity.

Enrollment projections show that even with proposed boundary changes, Douglass will be even more crowded by 2004, with a projected enrollment of up to 155 percent of capacity.

The Prince George's Board of Education is working on the boundaries, however, and they could still change.