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Sleuths track a forest killer Photo by Paul Fattig Plant pathologists Don Goheen, left, and Katy Marshall examine Port Orford cedar in the Williams Valley looking for clues on how to stop a fungus that is killing the trees. Scientists seek cure for Port Orford cedar disease By PAUL FATTIG WILLIAMS -- Don Goheen and Katy Marshall are tracking a silent killer. They've seen its trail of dead and dying in southwestern Oregon: They know where it lurks, when it strikes and how it kills. "It definitely is doing a lot of killing," Goheen said. "We've already lost a lot of the big trees." They are Forest Service plant pathologists intent on stopping Phytophthora lateralis, the deadly disease killing Port Orford cedar trees. The pathogen is commonly known as the Port Orford cedar root disease. It's a waterborne disease that moves stealthily through the forest, killing from the roots up. "You can walk down some creeks where every Port Orford cedar along the bank is dead in one short stretch," Marshall said. "Yet you can go to an adjacent stream where all the trees are healthy." The scientists -- Goheen is also an entomologist -- are the lead technical experts on the disease for the Forest Service and Bureau of Land Management in Oregon. Based at the Forest Service's Southwest Oregon Forest Insect and Disease Technical Center at the J. Herbert Stone Nursery in Central Point, they are working with others from the BLM, Oregon State University, Oregon Department of Forestry and the private sector. Last week found Goheen and Marshall conducting their scientific sleuthing along BLM roads in the Williams Valley, where treatment plots have been established. At one point Goheen pulled up a Port Orford cedar seedling, then scraped its roots with a pocket knife. The brown stain halfway up on the root indicates it is infected, he said. "This white material up higher is the healthy tissue," he explained. "When the stain gets up above the roots, they're not too long for this world." Unlike the more common incense cedar, Port Orford cedar, which has both ecological and commercial value, grows native only in southwestern Oregon and the northwest tip of California. It can be identified by its feathery boughs which made it a popular ornamental plant European travelers collected when they first arrived off the coast aboard sailing ships. It may have been the human practice of importing plants that is now causing the death of the stately trees. The disease, believed to have originated in Asia, was first discovered in the Pacific Northwest in a Seattle nursery in the early 1920s. It began to show up in Port Orford cedar stands in the early 1950s. Patches of dead, brown Port Orford cedar are now scattered throughout the region. "It's not likely it will exterminate everything," Goheen said. "But in terms of stand structure, elimination of the larger trees and killing many in riparian areas, it's a real problem." Goheen and Marshall aren't alone in trying to solve the threat. Last fall, the disease drew some of the world's top plant pathologists to southwestern Oregon for the first-ever global gathering of the International Union of Forest Research Organization. The group, which supports forestry research around the world, spent a week comparing notes on how to halt the advance of Phytophthora pathogens. The investigators are gathering clues that may eventually lead to stopping the killer in its forested tracts. They have found seedlings that are naturally disease resistant. Blocking off roads leading to infected areas appears to slow its advance, as does washing vehicles that have passed through an infected area. Disease spores have been found in the mud that clings to vehicles. The scientists also have created a dozen "sanitation" treatment plots in southwestern Oregon, spread throughout the Siskiyou forest and the BLM's Medford and Coos Bay districts. In these treated areas, Port Orford cedar have been removed in 25-foot to 50-foot swaths alongside forest roads to see if that stops the spread of the disease in that area. "The theory is that, if vehicles come along that have the organism on its tires, the disease won't be able to spread down into the general forest," Marshall said. "If you eliminate the Port Orford cedar along the roads, eventually it (the disease) will die out. That is the theory." Goheen and Marshall have been planting Port Orford cedar seedlings in the test plots to see if their method is working. They plant 10 12-inch seedlings between the road and the edge of the treated area. "This is our bait to see if the organism is still there," she said. Researchers have observed the fungus eventually dies away in an area where there is no Port Orford cedar to feed upon. "In order for it to survive for a long time, it has to be in the soil on a Port Orford cedar root," Marshall said. During their visit to the Williams Valley, the scientists removed Port Orford cedar seedlings planted in March in the test plots. The seedlings were taken back to the lab in Central Point where scientists will check to see if they are infected. "Our evidence so far suggests this really does have an impact on reducing it (disease) along the roads," Goheen said. "It doesn't do it immediately. The organism is pretty adroit at surviving for a few years." About three years after removing trees from an area, the scientists begin to see a reduction in the presence of the organism, Goheen said. "Until the disease dies away, the surface water flowing in the area could still pick up the organism and distribute it," Marshall said. "So you have to keep Port Orford cedar from coming back into an area until the disease is dead." Today's Edition : News | Sports | Business | Weather | Tempo | Classifieds Mail Tribune Copyright � The Mail Tribune 2000, Medford, Oregon USA