The Stanford University tree has been toppled for being drunk on the job.

The student wearing the costume of the legendary mascot was suspended from duty after UC Berkeley police observed her drinking from a flask during a Stanford-Cal basketball game last week, officials said Thursday.

"She was taking drinks inside the tree," said Kevin Klintworth, assistant athletic director at Cal. "The officers could see the flask through the costume."

Erin Lashnits, 23, a fifth-year undergraduate biology student, was given a breath test shortly after halftime of the Feb. 9 game at Haas Pavilion. Authorities said the test showed she had a blood alcohol level of 0.15 percent, nearly twice the legal limit for driving. She was cited for public drunkenness and told to leave the court but was allowed to watch the rest of the game from the grandstand.

Lashnits acknowledged that she was intoxicated but denied that she had a flask or that she had been drinking during the game.

"I apologize," she said. "I made a bad decision, and I wish I could take it back."

The defrocked tree, who plans to apply to become an astronaut and hopes one day to walk on the moon, said she could not believe the results of the breath test.

"I don't think these things lie, but I felt fine, and I was certainly able to do my job," she said. "I'd like to put this whole thing behind me. The last thing I want to do is hurt the Stanford band."

The band oversees the tree. Spokesman Sam Urmy said the incident began as a misunderstanding when Lashnits began prancing in the middle of the court, as she is allowed to do at Stanford, instead of confining her routines to under the basket, as Cal requires. That's when officers began observing her more closely, Urmy said.

"She wasn't doing anything offensive," Urmy said. "She was just jumping and dancing. The tree's movement is usually consistent with that of someone who's had something to drink."

The imbibing tree violated the terms of the band's three-year alcohol ban, which Stanford administrators imposed after band members got drunk on a notorious bus ride home from a USC football game in Los Angeles in 2003.

Urmy said the band would be picking a new tree next month. He said the band had relieved the tree of duty on its own accord, before the university took action.

"We wanted to take care of this ourselves," he said. "It's not that big a deal."