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Sudden Oak strikes state’s redwood trees

By David Scharfenberg Daily Planet Staff
Thursday September 05, 2002

California’s majestic coast redwood and Douglas fir trees are susceptible to a pathogen that causes Sudden Oak Death, UC researchers have confirmed. 

The discovery adds two more plant species to a growing list of 17 that can host the pathogen – Pythophthora ramorum – which has killed tens of thousands of oak and tanoak trees in California and Oregon since 1995, with no cure in sight for infected trees. 

UC researchers said it is unclear if the pathogen is fatal for coast redwoods and Douglas fir and that years could pass before its effects on the two species might be discovered. 

The long-term impact on the state’s ecology and economy, particularly its timber, nursery, landscape and construction industries, is also cloudy, the researchers said. 

But concern is growing outside the research community. Gov. Gray Davis said that in light of the new findings he sent a letter to President George W. Bush requesting $10 million in federal aid to fight Sudden Oak Death.  

The money would buttress the $2 million in state funding included in the 2002-2003 budget that Davis is expected to sign today. 

“Today’s announcement about Sudden Oak Death in Douglas fir and coast redwoods significantly raise the stakes,” Davis said in a statement Wednesday. “As a state, we will continue to tackle this serious economic and environmental problem but we need federal resources as well.”  

Additionally, the California Department of Food Agriculture announced Wednesday that it will restrict movement of coast redwood and Douglas fir from 12 California counties, including Alameda County, where the pathogen has been found. The restrictions already apply to the existing 15 plant species that are confirmed hosts. 

Researchers first discovered evidence of the pathogen on redwoods in January, but did not verify its presence until this week. 

UC Berkeley adjunct assistant professor of ecosystem science Matteo Garbelotto and UC Davis associate professor of plant pathology David Rizzo, the nation’s two leading researchers on Sudden Oak Death, made the confirmation after checking diseased trees in the wild and conducting tests in the lab. 

The scientists found infected redwood saplings in Jack London State Park in Sonoma County and Henry Cowell State Park in Santa Cruz County.  

They also found strong DNA evidence of diseased sprouts growing from the base of mature redwood trees in Marin, Monterey and Alameda counties – including a redwood tree on the UC Berkeley campus.  

Researchers first confirmed the presence of the problem on campus in November 2001, in other plant species. 

Garbelotto said that in recent months wherever researchers looked they found evidence in redwood trees, which suggests that the species has been susceptible to the pathogen for years. 

By contrast, researchers only confirmed its presence in one set of Douglas firs, in Sonoma County, suggesting that infection of that species may be new. 

Garbelotto also warned that there may have been something unique about the placement of the affected set of Douglas firs, found under a patch of heavily infected bay laurel trees. 

“We don’t know if there was something unique about that site that made the Douglas fir more susceptible to infection than in other areas,” he said.  

David Bischel, president of the California Forestry Association, an industry trade group in Sacramento, said timber companies have not yet found evidence of Sudden Oak Death on commercial land.  

Bischel said the industry’s chief concern will be preventing the spread of Phytophthora ramorum from urban and recreational areas to commercial logging territory. 

The organism spreads through cysts and spores that some of the affected species release during wet weather. The spores can travel in moist soil or through the air. People and animals can also track spores to uninfected areas. 

Ninety-five percent of the redwoods and 45 percent of the Douglas firs commercially harvested in California come from the 12 infested counties, according to Louis Blumberg, spokesperson for the Department of Forestry and Fire Protection. 

Citizens who believe they have an infected tree on their property should not chop down a tree or add water or fertilizer to a tree’s base, Garbelotto said, as these practices might just exacerbate the spread of the infection. 

There is no known cure but initial research shows that chemicals used to treat a similar pathogen in Western Australia may have prevented the pathogen’s spread there. 


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