The Fairfax County Board of Supervisors on Tuesday voted to save a 33-acre forest near Tysons Corner from development, citing the need for more green space in an area set to evolve into the county's new urban downtown.

The board voted 5-1, with three abstentions, to leave out of the county's Tysons redevelopment plans an extension of Boone Boulevard -- which is slated to run straight through Old Courthouse Spring Branch Stream Valley Park to the Dulles Toll Road.

"[This extension] would effectively take away green space at a time where we are looking for additional green space to add to the county's assets," said Supervisor Cathy Hudgins, D-Hunter Mill, who made the request to save the forest. "This seems counterproductive."

Hudgins' motion to thwart the extension comes nearly two months before the county releases the results of a study that will address the effects that an extension of Boone Boulevard, as well as other transportation projects in the county, would have on residents and the environment.

Supervisor Michael Frey, R-Sully, said he couldn't vote against the extension without knowing what its impact on the area will be.

"I'm happy to look at it, but I'm not expressing my opinion ... before the study is in front of us," Frey said.

Leading the charge against the extension is a group of 15 Fairfax civic associations that started a movement against the proposed development nearly two years ago. Among their concerns is that development in the area would cause a spring running through the forest to flood.

Pam Konde, president of the Save Tysons Last Forest coalition, who had hoped the board would take the extension completely off the table, said she was mostly pleased with the board's decision.

"Enough is enough," Konde said. "It's not just us neighbors who want to save our trees and the stream valley, it's the whole county. Every dollar spent is a waste of funding -- funding that should be going towards other countywide transportation problems."

Supervisors John Cook, R-Braddock, Pat Herrity, R-Springfield, and Linda Smyth, D-Providence, abstained from the vote, citing confusion with the motion and concerns with forming an opinion about the extension before learning the results of the environmental study.

County staff are scheduled to present the findings of the environmental impact study on Jan. 15 at a meeting of the board's Transportation Committee.