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Oak-killing spores found in redwoods Scientists are awaiting the results of lab tests to see whether the trees are acting as hosts or could become infected From wire and staff reports A shudder went through the redwood-loving world this week with news that the towering trees may be susceptible to the disease that has been laying waste to California oaks. Scientists are still waiting for the results of lab tests to see whether redwoods are acting as hosts or could become infected. The disease, called sudden oak death, has killed tens of thousands of black oak, coast live oak and tan oak trees from Monterey County near San Francisco to the southern Oregon coast, about 500 miles north. Camp sites have been closed and trees chopped down to try to contain the contamination. No evidence of the disease, however, has appeared in Humboldt and Del Norte counties, home to several state and national redwood parks. The 40 acres of infested tan oak found last September near Brookings have been eradicated and no other traces of the disease have been found in the state, said plant pathologist Ellen Goheen of the U.S. Forest Service, Central Point. "This information (about the redwoods) got out way too early. It's highly preliminary," Goheen said. "The presence of the pathogen doesn't mean redwoods are susceptible. They were in a heavily infested area (of oaks) and there were a lot of fungal spores around. It would be pretty hard for the redwoods not to have spores on them." The disease-causing organism, Phytophthora ramorum, is related to the same type of organism believed to have caused the Irish potato famine in the mid-19th century. No cure has been found. The disturbing new discovery is that DNA from Phytophthora ramorum spores has been extracted from coastal redwood sprouts. Sprouts are how redwood trees reproduce; when a redwood dies, a new tree grows from one of its sprouts. Matteo Garbelotto, a forest pathologist from the University of California, Berkeley, says tests are now being conducted to see whether the spores are simply on the surface of the tree or whether they have burrowed into the tissue, meaning the redwoods can be a host. Plant experts also have injected healthy redwood sprouts with the disease to see whether they become infected. Results are expected in a few weeks. However, even if they show redwood sprouts can be infected, it would be several months before researchers will know whether big trees also would succumb, Garbelotto said. "The worst-case scenario is that, yes, large trees will be susceptible and that in some areas there's going to be a lot of mortality of redwoods," he said. "More than that, I can't say. It's rare to see a microorganism completely wipe out a tree." Even if lab tests show the redwood only acts as a host, it could prove ruinous to the state's timber industry and dwindling old-growth forests. A current statewide quarantine limits the movement of wood products containing the pathogen. Such a finding in redwoods could make it hard for companies to get their lumber to mills. California also has closed many campsites and is urging visitors to infested areas to wash cars, mountain bikes and shoes before leaving. To safeguard Oregon from the infestation, the Forest Service, Bureau of Land Management and state Forestry and Agriculture departments have burned and quarantined the Curry County hot spot. All summer and fall, the agencies ran aerial surveys and foot patrols looking for the fungus in Southern Oregon, Goheen said, but found nothing outside the Brookings infestation. Agencies have handled several inquiries about plastic-wrapped oak firewood brought in from Mendocino County and put on sale at Fred Meyer in Medford, she said. "But we checked these out and they're clean. They were harvested before any disease was found there." The main concern of arborists here is the disease jumping into the madrone stands of Southern Oregon, said Phil Frazee of Arbor West Tree Experts, Eagle Point. "Their stress level is high because they're trying to rebound from the drought. They've got about 20 percent leaf cover in a lot of places and that makes it easier for a pest to move in." As for the redwoods, it's still too early to know the extent of the threat, Goheen said. "It's a new disease that's still trying to figure out what its hosts are," she said. "It hasn't really settled in and evolved yet and we have yet to know the full story of it." On the Net: Oak Mortality Task Force, www.suddenoakdeath.org/ Mail Tribune Home | Ottaway Newspapers, Inc. | Dow Jones & Co., Inc. | Privacy | Contact Us Copyright � 2001 Mail Tribune, Inc.