Sierra Club
Redwood Chapter Newsletter
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Sudden Oak Death Threatens Janice Alexander | |
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In the last 200 years, California has lost more than a third of its native oak woodlands to agriculture and urban development. The remainder is in steady decline due to California's burgeoning population, shifting trends in agriculture and competition with non-native grasses. Efforts to curb the negative impacts of suburban sprawl and agricultural conversions of oak woodlands have been underway for years, but now there is a new attack on California's threatened oak woodlands - a new pathogen, threatening to irrevocably change the small amount of remaining forest. Sudden Oak Death is a forest disease that is artificially spread through infected horticultural plants and human activities. It is killing thousands of trees and impacting California's richest terrestrial habitat. The consequences of Sudden Oak Death include increased risk of tree failure and an altered visual landscape as large swaths of susceptible oaks and tanoaks die. This change in forest composition impacts ecosystem functions and reduces food and habitat for wildlife. There may also be changes in water quality and supply and fire cycles. Adverse economic impacts have already been felt by local parks and municipalities dealing with this disease on their lands. The disease is caused by the invasive pathogen Phytophthora ramorum, confirmed in 13 California coastal counties, one county in southern Oregon, and in Europe. Though the origin of the pathogen is not known, the limited number of clones, its wide host range, and its virulence, indicate that P. ramorum is not native to California. Despite federal and state quarantines, inspections show that the pathogen moved from California nurseries to nurseries in Oregon, Washington and eleven other states across the country. Additionally, the European clone of the pathogen was recently detected in nurseries in British Columbia, Washington and Oregon. |
It is clear that human activities, especially in horticulture, play a large role in moving the pathogen long distances. While the pathogen is limited in its current distribution, the potential risk to the rest of the country and other parts of the world is great. What you can do: Consider where you're going. Familiarize yourself with symptoms on host plants and avoid visiting infested areas whenever possible. Do not move plants or soil from infested locations.
More information can be found at the web site of the California Oak Mortality Task Force: www.suddenoakdeath.org. |