Californian study confirms "sudden death" hits redwoods
Date: 06-Sep-02
Country: USA
Author: Andrew Quinn
Gov. Gray Davis immediately asked President George W. Bush for $10 million to fight the blight fungus, which he said could have a severe economic impact on the state.
"The implications of this disease are enormous, including a major change in the environment and landscape of California, severe economic dislocation, and an increase in fire danger - especially problematic in areas with high population density," Davis said in a letter to Bush.
Wednesday's announcement was grim news for admirers of California's majestic redwoods, which can reach heights of more than 350 feet (116 metres) and live to be 2,000 years old. It may also spell trouble for the state's timber industry, which could face quarantines and lumber sales restrictions if the microbe is found to be widespread.
A KILLER FUNGUS
Confirming indications first detected in January, University of California researchers said they had proved that the Phytophthora ramorum microbe - a contagious, algae-like organism related to the species responsible for Ireland's potato famine of the mid-1800s - was now infecting both redwoods and Douglas firs.
Matteo Garbelotto, the Berkeley forest pathologist credited with identifying the so-called "Sudden Oak Death" syndrome in the late 1990s, said thus far scientists had found symptoms only in tree saplings, making it difficult to predict how the disease would affect full-grown trees.
"Since we have not seen evidence of disease symptoms or death from the pathogen in large, mature redwood or Douglas fir, we cannot say what the effects of the infection will be long-term," Garbelotto said in a statement.
First detected in northern California's Marin County in 1995, the Sudden Oak Death pathogen has killed tens of thousands of coastal oak and tanoak trees and become one of the state's major environmental battles.
The disease has also steadily spread to other species, now affecting some 17 types of plants including rhododendrons, California bay laurel trees, Shreve's oak, madrones and wild huckleberries.
While infested oaks die quickly, other carriers of the disease can exhibit less severe symptoms, including blotching leaves and withering of branches and new sprouts, leaving trees alive but less able to regenerate and propagate.
A SPREADING PLAGUE
The California researchers said they located the infected Douglas fir saplings in Sonoma County, and the redwood saplings in both Sonoma and Santa Cruz counties.
The researchers also conducted DNA tests on diseased sprouts growing from the base of mature redwood trees in Marin, Alameda and Monterey counties - indicating the presence of the pathogen was widespread.
"It seems that some species are able to tolerate the pathogen better than others," said David Rizzo, associate professor of plant pathology at UC Davis.
The affected redwood saplings showed lesions and discoloration on individual needles, while redwood seedlings exposed to the fungus exhibited lesions and discolored branches. Douglas fir seedlings exposed to the fungus developed even larger lesions.
The discovery that the "Sudden Death" microbe has now spread to conifer species could be worrying for California timber growers, who noted that redwood and Douglas firs made up more than 50 percent of the state's wood and wood product sales in 2001.
While Oregon has already imposed a quarantine on nursery stock and wood products from infected species, and California itself regulates movement and sale of infected timber products from affected counties, California's timber industry was taking a wait-and-see approach before ringing the alarm bells.
"It's too early to tell how this will play out," said Butch Bernhardt, a spokesman for the Western Wood Products Association. "We still don't know enough about this disease, or how it spreads."