Fungus-killed trees fuel a hotter, faster Big Sur blaze

Firefighters battling to protect Big Sur are working in forests riddled with thousands of flammable dead trees, making the savage Basin Complex fire burn hotter and travel faster, forest experts say.

Hundreds of thousands of tanoak and oak trees in the area have been killed in recent years by a disease known as sudden oak death, producing fuel that allows flames to spread more quickly through redwoods and other evergreens, they said.

Firefighters also complain of smoldering tanoak logs that keep the ground treacherous even after the flames pass through, said Jeff Kwasny, Big Sur ecosystem manager for the Los Padres National Forest.

“Typically in this country, the fire just moves through. Now, the fire moves on, and it leaves these dead trees still burning away, like a log left in your fireplace,” he said.

Although the massive oak die-off has swept through forests lining California’s central and northern coasts, the Big Sur area is especially hard hit.

“You look in some of these canyons, and you’ll see 70%, 80% of tanoaks are dead,” said UC Davis plant pathology professor David Rizzo. He estimates that 1 million dead oak trees can be found in a 200,000-acre sweep of Big Sur forest that he has examined for the last three years in a federally funded study of the disease. That number was confirmed by John Kelly, a retired U.S. Forest Service forester who conducted aerial surveys of dead trees in area forests.

Sudden oak death has been traced to a fungus-like organism, Phytophthora ramorum, that can attack tanoaks, coast live oaks and California black oaks. Scientists believe it was transported on nursery stock to the United States, where it was first reported in California in the mid-1990s.

Among the hardest hit is the tanoak, a major component of the redwood and mixed evergreen forests common on the Big Sur coast. It is not a member of the oak family, although it has acorns and oak-like leaves and can grow 60 to 80 feet tall. Its range extends from Oregon to Central California.

Trees can take several years to die, and there is no known cure. In an effort to avoid spreading the disease, firefighters are required to wash and decontaminate their engines and tools before leaving Big Sur.

U.S. Forest Service ecologist Lloyd Williams said dead tanoaks were most prevalent on the fire’s western slope, representing about one-third of the 72,000-acre fire area. Since many of the dead oaks are still standing, Williams said, “The fire can go up the tree and burning embers can spread.”

The searing heat slows down crews, and standing trees can topple, putting firefighters at risk. Some logs may smolder for the rest of the summer and may kill redwoods by burning their root systems, Rizzo said.

The disease fares best in warm, moist weather, and the wet springs of 2005 and 2006 appear to have hastened its spread, he said. It is not commonly found south of Monterey County, and experts believe Southern California is too hot and dry to support it.

--

More information is available at www.suddenoakdeath.org

--

deborah.schoch@latimes.com

--

Times researcher Robin Mayper contributed to this report.