One of the tree sitters is John Quigley, the man who camped out for 71 days in an oak tree in Santa Clarita in 2003.
"They definitely need to back off. Otherwise, they're seriously going to endanger our lives here with these cranes," Quigley said during a telephone interview with Eyewitness News.
Despite the presence of the protestors, county officials brought in heavy equipment to remove close to 200 trees on 11 acres, including more than 179 oaks, which environmentalists are vowing to save.
"They're willing to stay there until hell freezes over. They're trying to take down a lot of trees and it's unnecessary. There's enough room for the sediment on another pile," said Arcadia resident Glenn Owens.
"This is not just one or two trees here and there. It's what we call an oak woodland habitat," said David Czamanske of the Sierra Club. "It's very unique, very rare here."
The standoff came as the county got orders from the state to clear the area of vegetation and turn the 11 acres above Arcadia into a sediment collection area. The Santa Anita Dam is filling with silt and mud and must be cleared to alleviate pressure on the dam walls, which are not up to seismic standards.
"The project itself has been fully approved by all the regulatory agencies that are required to approve it at a federal and a state level," said Bob Spencer of Los Angeles County Public Works.
County officials said the 11 acres were purchased 60 years ago just for this purpose. And while opponents suggest another location, the county said each area is supposed to take care of its own debris.
"The water that is stored behind that reservoir serves the entire city of Sierra Madre and 75 percent of the city of Arcadia," said Spencer.
Some residents agree that the county's plan should move forward.
"I know everybody likes trees and that, but we have to look at the betterment of it. From what I understand, they're trying to clear out some of the sediment. And if they don't, I'm afraid it may cause floods and more property damage," said Arcadia resident Paul Snyder.
Still, protestors insist there has to be another way.
"We believe there are several other alternatives that they could do, without delay of cost, without delay of time, that are quite reasonable," said Czamanske.