BERKELEY — Negotiations between tree sitters and UC Berkeley ended Monday, leaving the university to consider how to safely remove the four activists from their perch within the next day or so.

Just two redwoods remain standing in front of Memorial Stadium. One of the trees is occupied by four men who refuse to come down even though the grove they have been trying to save for the past 21 months is gone. Nearly all that remains is dirt and the occupied, but mostly shaved redwood with a few branches, tarps, wooden platforms and pulleys at its top. The men in the tree wait, occasionally skillfully moving from one side of the tree to the other and sometimes shouting greetings to the crowd below.

The university has used a cherry picker and trained arborists in the past to bring down tree sitters who were willing to descend, but university officials have also said the method is dangerous. Just how the university plans to bring down the men in the next day or so remained unclear Monday.

"We're not going to talk about that," UC Berkeley spokesman Dan Mogulof said at an afternoon press briefing. "What we are going to do is remove them safely."

The men in the tree go by the names Shem, Huck, Ernesto and Mando.

Asked what will happen if the university tries to forcibly remove them, tree siter Huck said, "We plan on standing our ground and standing for what we believe in. We really hope it doesn't come to that."

The university cut off deliveries of food and water to the tree sitters at 9 a.m. Monday, but university officials said the tree sitters have some food and water stockpiled. The university gave the tree sitters a 72-hour notice Friday and tried all weekend to negotiate with them, even conceding to allow the group and their supporters have a say in future land-use planning.

But in the end, the tree sitters did not come down from their tree-top post.

"They just couldn't come to an agreement among themselves," Mogulof said. "We spent a lot of time over the weekend talking to these people, and we spent a lot of time and effort on a proposal that, to the best of understanding, addressed their concerns going forward. At this time, we have no choice but to move forward."

Mogulof said a professional mediator crafted the proposal — which was signed Sunday by university Vice Chancellor Nathan Brostrom — agreeing to give the tree activists a say in land-use decisions, in UC's future donations to environmental causes, what happens to the stump of the "grandmother oak" from the grove, among other things, if the tree sitters would come down.

"We were willing to talk about a lot of things," Mogulof said.

But apparently the ground supporters advised the tree sitters to stay put, and the university said enough is enough and called an end to talks.

Tree sitters and their supporters said the characterization that activists were ready to come down but the ground support people talked them out of it is completely false.

Ground supporter Erik Eisenberg, who goes by the name Ayr, said the tree-sit ground supporters made a proposal to the university Sunday, which included two requests. They asked that the university to create an oversight body composed of community members, neighborhood association members, Native Americans and environmentalists who would give input on UC's future land-use planning process "so we never have something like this happen again," Eisenberg said.

They also requested that "reparations be made for the damages." Specifically, they asked for donations to land conservations efforts and nonprofit Native American groups.

For most of Monday, a group of 30 to 50 people — supporters of the protest, students and tourists — mulled around outside the former grove site waiting for something to happen. Nothing ever did.

The trees were on the site of a planned $140 million sports training facility, which lawsuits have blocked since December 2006, when the tree sit began.

But the protesters and their supporters have lost a series of court challenges, and the university has court clearance to proceed with the project. The university has for the last few months been allowing the ground support team to send up water and one bag of food daily, but none went up Monday.

Bulldozers and chain saws have razed all but two redwoods. The smaller redwood is slated to be transplanted to another site on the Berkeley campus because it has a good chance for survival, Mogulof said. The larger tree, its lower branches lopped off, now looks like a big, bare stalk of celery with a cluster of branches containing the four remaining tree sitters at the top.

Kristin Bender covers Berkeley. Reach her at kbender@bayareanewsgroup.com. Read her blog at www.ibabuzz.com/outtakes.