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California and the West

Scientists Fear Mysterious Killer Could Devastate Country's Oaks

Infestation: There is no cure for the aggressive new disease, which may already have claimed hundreds of thousands of trees in coastal areas.


The rapidly spreading death of Northern California coastal oaks is causing mounting alarm among state and federal scientists who have no cure for a deadly new disease that could ravage the state's signature tree and perhaps move across the country.

First detected five years ago among little-valued tan oaks, the disease known as sudden oak death is now attacking prized coast live oaks and black oaks, turning hillsides a desolate brown.

"It's a nightmare," U.S. Forest Service plant pathologist Susan Frankel said of the disease's potential for devastation.

Her agency has requested a quarantine to stop the removal of infested oak stock and deadwood from affected areas, and the state recently created a multi-agency task force headed by Frankel to control the disease.

But there are complaints that the state moved too slowly when the dieback first appeared.

"From 1995, we have had all this time, and now it's an emergency," said Janet Cobb, president of the private California Oak Foundation. "Basically they ignored it."

There is much scientists don't know about the disease, but they believe it is caused by a recently discovered fungus that, in Frankel's words, "doesn't match anything that's been seen anywhere."

It is extremely aggressive. In some areas, 80% of the oaks are infected and half of those are dead. The disease has been confirmed in Sonoma, Napa, Marin, Santa Cruz and Monterey counties and is suspected in several others.

Researchers don't know how many oaks have died, but Frankel said inspections suggest the toll may already be in the hundreds of thousands.

Marin County is especially hard hit.

"I can see on a daily basis more trees dying," said county Supervisor Cynthia Murray. "It's a complete disaster. We're devastated."

Marin's coast live oaks are beloved. People build their houses around them. Spreading majestically across the Northern California hills, the trees add thousands of dollars to the value of a property and provide food for wildlife.

"What we're looking at is a permanent environmental change," Murray said.

Once a stand of trees dies in the wild, it becomes a fire hazard. Homeowners must spend $1,000 to $2,000 to have a dead oak cut down. Then there is the question of what to do with the infected dead wood. The public is being advised not to remove it from the area to avoid spreading the disease.

Scientists are scrambling to find out more about the dieback, but need more money.

"It's terribly underfunded," Frankel said of research and control efforts. So far, roughly $200,000 in federal and state money has been spent on the problem.

A $5-million request by the state Department of Forestry and Fire Protection for research, tree removal and prevention programs never made it out of the Legislature this year. The funding proposal will be renewed when state lawmakers reconvene in January.

The tree deaths did not at first attract widespread concern because they involved tan oaks, "a species that very few people care about," Frankel said. Moreover, the oozing bark and beetle infestations that accompany the disease could have been caused by a number of things.

Interest escalated as the infestation hit more valued species, growing not only in the wild but also in residential backyards and on suburban hillsides.

Then, in late July, UC Davis plant scientist David Rizzo identified a fungus that is the probable cause of sudden oak death. The pathogen is related to the organisms that devastated Ireland's potato fields in the mid-1800s, causing famine and mass emigration.

Thus far, Frankel said, sudden oak death has been confined to within 20 miles of the coast. But researchers do not know if that is because it hasn't had enough time to migrate inland or if it requires certain environmental conditions that restrict its range.

Some of the species infected in California belong to the red oak group, one of the dominant types of oaks in the East, raising concerns that the disease could become a national epidemic akin to the Dutch elm disease that wiped out many of the country's elm trees.

The fungus favors cool temperatures and moisture, so if it gets into the Sierra foothills, it could kill the region's black oaks.

Scott Johnson, chairman of the California Forest Pest Council, defended the state's response.

"I think they're reacting extremely quickly," said Johnson, whose group advises the state Forestry Board and suggested the special task force.

Frankel is not so sure. "A coordinated response is overdue and more assistance to the counties that have [the infestation] is overdue," she said.

The Forestry Board received a nudge from state Resources Secretary Mary Nichols last week when she met with members to discuss a lawsuit recently filed by Cobb's group and the Mountain Lion Foundation.

The San Francisco Superior Court suit charges that the state Forestry Board and department have failed to adequately protect oak woodlands by not requiring permits for oak removal.

While Nichols said in an interview that she disagrees with the premise of the suit, she suggested that the board take a greater role in saving oaks, whatever the threat.

Forestry department spokesman Louis Blumberg said: "Secretary Nichols provided additional impetus for the board and department to take more action [regarding sudden oak death] and we are responding at this point. I'm not sure what that's going to look like."

Fungus Threat

A new disease is attacking three species of oak in Northern and Central California. Believed to be caused by a fungus, sudden oak death has so far been found no farther than 20 miles from the coast, but scientists are concerned it may spread inland and to other states as well.

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