Bulldozers finished demolishing the 11 acres of oak tree woodlands in Arcadia, at the Los Angeles County Santa Anita Dam Sediment Placement Site yesterday. Four environmental activists, called "tree-sitters," were booked on trespassing and obstruction, then were later released. Los Angeles County Public Works said demolishing the 179 trees to make room for sediment dredged from nearby dams is a flood control effort necessary to ensure public safety. The bitter debate continues. Activists claim the project was not transparent to the public and media.