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Oak tree disease could spread north Mail Tribune / Bob Pennell Jackson County work crews take care of oak trees near the Medford branch of the county library. Diseases such as "sudden oak death" have yet to make an appearance in Southern Oregon, but the deadly fungus can be transmitted in ways such as through the clothing, cars or mountain bikes of people who have visited infected areas. California�s mighty oaks have fallen prey to deadly pathogen By Paul Fattig Plant pathologist Don Goheen has stood among the dead and dying of the once stately oaks in Northern California. He came away impressed � and concerned � with the pathogen dubbed "sudden oak death" (SOD) which has been swiftly killing them. "This is something we definitely don�t want here," Goheen said, then added, "As far as we know, it�s not here. But they have found cases pretty far north." Officials are asking the public to take precautions, such as washing vehicles after they�ve gone through an area where oaks have died from the fungus, to help keep the oak-killing fungus from spreading into Southern Oregon. The fungus Phytophthora invades tanoaks, black oaks and coastal live oaks, killing portions of the trees. The oaks are then weakened, and fall prey to insects and other fungi. "This appears to be a new species," Goheen said. "We didn�t even start hearing about it until five years ago. The closest thing to it is probably the organism that causes Port Orford cedar root disease." Goheen, who is also an entolmologist, is one of the top scientists for the Forest Service and Bureau of Land Management studying the pathogen devastating Port Orford cedar in Western Oregon. He is based at the Forest Service�s Southwest Oregon Forest Insect and Disease Technical Center at the J. Herbert Stone Nursery in Central Point. Unlike the fungus which kills Port Orford cedar from the roots up, the oak killer attacks the bark. Trees suffering from sudden oak death often bleed burgundy-red to black sap from their bark, develop sunken or flattened cankers beneath the bleeding and a distinctive dark red canker margin in the bark and wood. The symptoms usually occur with three to 15 feet of the ground. Once infected, trees do not recover. Local residents should be aware that oaks also succumb to other diseases, droughts and infestations, observed Chuck Miller, service forester for the Oregon Department of Forestry in Jackson and Josephine counties. "We have a lot of oak mortality that�s natural," Miller said. "We go through a drought. They die. There is root rot in soil that affects white oak. So when an oak dies, that doesn�t mean it�s from sudden oak death." But the symptoms of the latter stand out, he said. "The description of the mortality, cracks in the bark and the weeping, that�s not a common thing seen in oaks," Miller said. "And these trees die suddenly." In fact, young tanoaks often die within three weeks of the fungal infection, according to scientists. If the disease were brought to Southern Oregon, it would have a major impact, he said. "Oaks play an important role in our area," Miller said. "Their biggest niche is providing habitat for wildlife." Surveys of oaks in the region have yet to find the disease in Southern Oregon, he said. "As far as we know it�s not in Southern Oregon yet," Miller said. "But it�s a pathogen. It can be brought here." Thus far, most of the oaks dying from SOD are in the San Francisco Bay area, although trees with SOD-like symptoms have been found as far north as Humboldt County. Last spring, Goheen and other scientists spent some time studying the deadly outbreak in the northern Bay area. "We did some surveys up here, particularly along the coastal area," he said. "We found a few trees that had symptoms that were similar (to SOD) but we didn�t find it." More surveys will be conducted next spring, he said. "There is quite a lot of research going on now," he said. "But it�s still early in the discovery phase." With no cure on the immediate horizon, the only option is to prevent its spread, he said. "Oaks here are extremely significant for wildlife," he said, noting the trees are also a source of beauty to local residents humans. "We don�t want to lose those trees." Reach reporter Paul Fattig at 776-4496 or e-mail him at [email protected] Mail Tribune Home | Ottaway Newspapers, Inc. | Dow Jones & Co., Inc. | Privacy | Contact Us Copyright � 2000 Mail Tribune, Inc.