A task force made up of horticulturists, agronomists and engineers had determined that the area directly adjacent to the trees does not show high concentrations of the dangerous toxin, Auburn spokeswoman Deedie Dowdle said.
"We were very concerned that the herbicide would spread. This particular one has been known to kill everything in a very large area, up to an acre," Dowdle said.
Dowdle said that new, clean soil mixed with activated charcoal was installed around the trees. The charcoal's purpose is to try to pull away any remaining herbicide in the soil, she said.
Workers began removing the highly contaminated dirt earlier in the week, after conducting extensive tests to see just how far the poison traveled through the grounds. As a precaution, the workers were also removing several areas outside beds around the trees that have shown elevated levels.
Although it's unknown how much of the poison the live oak roots took in, Dowdle said the task force was encouraged with their progress.
"Obviously we're very concerned about the trees, given that they were given 65 times the dose than what would be necessary to kill them," she said. "But they feel a bit better. We had thought there was virtually no chance, and now we're just hoping."
Auburn police arrested Harvey Updyke Jr., 62, last week for allegedly dousing the landmark trees with herbicide so potent that agronomists said the two 130-year-old trees on Toomer's Corner have little to no chance of survival.
Updyke has been charged with one count of criminal mischief and has been released on $50,000 bail.
"At this time, we have no other suspects," Auburn Police Chief Tommy Dawson said Friday.
Updyke has cycled through three court-appointed lawyers and is currently being represented by Glennon Threatt Jr., a Birmingham-based attorney, according to court documents.
Attorney Jerry M. Blevins said Tuesday that he was retained on the matter last week but withdrew from the case, based on "some conflicts between me and Mr. Updyke."
Updyke's two previous court-appointed attorneys were allowed to withdraw because of their affiliations with Auburn University.
Authorities first learned of the herbicide after a caller who identified himself as "Al from Dadeville" phoned into a Birmingham, Alabama, radio talk show, saying he had poisoned the renowned live oaks after Auburn won a contentious November football game against the University of Alabama. "Al" ended the call with "Roll Damn Tide," a battle cry for the University of Alabama.
Fans typically gather around the trees after victories, draping them with toilet paper, said Mike Clardy, Auburn University spokesman. Clardy said it's not just Auburn supporters who have rallied around the trees, however.
"We've had hundreds of calls of encouragement and suggestions from other schools in the SEC, including from the University of Alabama," he said, referring to the Southeastern Conference, which includes Auburn and the University of Alabama.
Friday, a Facebook page called "Tide for Toomer's" said more than $47,000 had been raised in support of the historic trees.
Dowdle said that sum, combined with the amounts contributed through Auburn and its partnerships, brings the total donation to more than $100,000.
"Isn't that fantastic?" Dowdle said. "On the field, there's a tremendous rivalry, but off the field, there's a tremendous respect."
Student body presidents of the longtime rival schools announced earlier in the week an initiative to plant sister trees on each other's campuses, in an expression of joint unity.
"Our rivalry is more than a game. It's a partnership. More times than not, it unites us instead of dividing us," James Fowler of Alabama said. The unity trees will be planted within the next months.
The next step for the Toomer's Corner trees, Dowdle said, is to see whether the live oaks produce leaves come spring.
"Depending how long the poison was in the soil and taken up by the roots, in spite of the rain," she said. "We're just going to wait and see. Everybody is giving it their all."