Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Nathan Rank; Hall Cushman; Ross Meentemeyer
    Date: 2008
    Source: In: Merenlender, Adina; McCreary, Douglas; Purcell, Kathryn L., tech. eds. 2008. Proceedings of the sixth California oak symposium: today's challenges, tomorrow's opportunities. Gen. Tech. Rep. PSW-GTR-217. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: pp. 197-198
    Publication Series: General Technical Report (GTR)
    Station: Pacific Southwest Research Station
    PDF: View PDF  (20.14 KB)

    Description

    Woodland ecosystems often consist of a mosaic of interacting dominant woody species that vary in density and abundance. Local variation in dominant species abundance may influence spread of plant pathogens across this heterogeneous landscape. We investigated this possibility in a 275 km2 study area in eastern Sonoma County, which is being invaded by the pathogen that causes Sudden Oak Death, Phytophthora ramorum. We assessed symptoms of infection by P. ramorum of foliar and canker hosts in 2004 and 2005 in 202 randomly located plots. Our results showed that the widespread foliar host, bay laurel (Umbellaria californica), exhibited symptoms of disease throughout the study area, while canker hosts showed no signs of infection in most plots. This suggests that SOD spread among foliar hosts much more rapidly than from foliar hosts to canker hosts. With the high precipitation over the past two rainy seasons, we expect the disease to progress into canker hosts over the next several years. We also found that density of bay stems and degree of infection on bay laurel depended partly on presence of oak species. For example, the proportion of bay stems with symptoms of P. ramorum was 18% greater when coast live oak (Quercus agrifolia) was present than when it was absent. Coast live oak presence was also related to number of symptomatic bay leaves per tree. We suspect that our findings arise from the fact that the pathogen spreads most rapidly in stands where few canker host individuals inhibit dispersal among foliar host trees. Although previous studies have shown that abundance of bay laurel is related to infection levels in oaks, this is the first study that we know of suggesting that the presence of canker hosts affects infection levels on bay laurel, the main foliar host of P. ramorum.

    Publication Notes

    • You may send email to psw_communications@fs.fed.us to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

    Citation

    Rank, Nathan; Cushman, Hall; Meentemeyer, Ross. 2008. Woodland structure affects intensity of infection by an exotic forest pathogen. In: Merenlender, Adina; McCreary, Douglas; Purcell, Kathryn L., tech. eds. 2008. Proceedings of the sixth California oak symposium: today's challenges, tomorrow's opportunities. Gen. Tech. Rep. PSW-GTR-217. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: pp. 197-198

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page