Sonoma County supervisors on Tuesday slammed a proposed tribal housing and cultural center in Windsor, saying a final study of the project downplayed impacts on the environment and public services.

The Lytton Band of Pomo Indians want to build up to 147 housing units on 124 acres they own near the town's southwest border.

To do so they would have to cut down about 1,700 native oak trees, a move the project's final environmental assessment described as a marginal biologic or scenic loss.

Supervisor David Rabbitt, an architect, called the site plan "horrible" and the tree clearing "unconscionable."

"I'm sorry. This is one of the most healthy blue oak woodlands in the county and there would be an absolute impact," said Supervisor Mike McGuire, who represents the area.

He joined with other board members in calling for a more detailed environmental impact study, a request the county will make in a 18-page letter to the Bureau of Indian Affairs, the lead regulating agency.

A tribal spokesman this week called the current assessment "very comprehensive," saying the tribe saw no need for a more detailed study.

But supervisors said the Lytton Pomos, unlike other tribes with developments in the area, have failed to recognize or discuss the increased demand for services, including fire, medical and law enforcement from their project — none of which will be paid for because residents will not be subject to county property tax.

"This board is saying they must come forward and pay their share, just like any development," said McGuire.