High up on Frowning Ridge, the poison oak is potent and rattlesnakes slither through the bushes, but chain saws and tractors are removing the area's greatest risk.
UC Berkeley and several other agencies are clearing tens of thousands of eucalyptus and Monterey pine trees from the Oakland and Berkeley hills, hoping to prevent future fires from turning into catastrophes.
For university officials, most of the work is focused on the hundreds of acres of wilderness south of Grizzly Peak, mostly within the Oakland city limits. Officials estimate as many as 150,000 eucalyptuses and Monterey pines are on UC Berkeley's hills; they plan to remove up to 50,000 trees.
Neither species is native to the East Bay, and both present major problems for firefighters and fire-prevention planners. Each played an important role in the spreading of the deadly 1991 Oakland hills fire.
UC Berkeley has been lucky so far. The 1991 fire burned only a small corner of uninhabited hillside land, while a catastrophic 1923 blaze devoured homes up to the university's northern border.
Officials hope the combined efforts of the university and its neighbors will slow or stop fires coming from Tilden Regional Park, Orinda or surrounding areas, said Tom Klatt, UC Berkeley's emergency-planning manager.
"The ridge would be the firebreak," he said, standing alongside Grizzly Peak Boulevard on Friday. "The firefighters wouldn't come up here if it was a forest. It would be a death trap."
The easiest management techniques could save homes and lives, said Tom Parker, a San Francisco State University ecologist. The most dangerous wildland fires spread through the canopies of fully grown trees, he said.
"Even if you just thin (the trees) out, it will keep the fire on the ground," Parker said. "The intensity will be much reduced."
Eucalyptuses were first imported from Australia and have flourished across California. They grow 15 feet per year and crowd out native plant and animal species, and their bark sheds during fires, carrying embers a mile or more.
The same characteristics that have made eucalyptus trees attractive to Californians also make them dangerous, said Kristine Shaff, a public-outreach coordinator with Oakland's Wildfire Prevention Assessment District, approved by property owners last year.
"You know that great eucalyptus smell?" Shaff said. "Well, that's a sap and it's flammable."
Monterey pines also grow rapidly and can reach 100 feet, but their relatively short life span of 60 years has left hundreds of dead or dying trees spanning the East Bay hills.
Using several state and federal grants, agencies have started thinning out the trees, but keeping the hills and the UC Berkeley campus safe demands constant vigilance, Klatt said. Eucalyptus in particular is difficult to eradicate.
"Here's our nemesis here," Klatt said, pulling out a 5-inch-tall eucalyptus seedling from a recently cleared area.
A couple of hundred feet from Grizzly Peak Boulevard, two men cut tree after tree Friday on a hillside with spectacular panoramic views of San Francisco Bay. After each tree fell, one man sprayed the stumps with blue-tinged herbicide to stunt future growth, a practice that keeps 50 percent to 90 percent of the trees from returning, Klatt said.
But the task appeared nearly fruitless in some parts of the site.
Three-month-old eucalyptuses -- already 8 feet tall -- had sprouted from freshly cut stumps. Some eucalyptus clusters included three generations of trees.
"This is a testament to our failure," Klatt said. "Miles to go before I sleep."
Distributed by the Associated Press