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): Michael C. Wimberly; Thomas A. Spies
    Date: 2002
    Source: Ecosystems. 5: 232-243
    Publication Series: Scientific Journal (JRNL)
    PDF: View PDF  (2.2 MB)

    Description

    Tsuga heterophylla (western hemlock), a fire-sensitive, late-successional tree species, is an important component of old-growth forests in the Pacific Northwest, USA. In the Oregon Coast Range, however, T. heterophylla occurs at low densities in or is completely absent from many conifer stands. We used a cellular automata-based simulation model to explore the influences of the fire regime and gap disturbances on T. heterophylla dynamics at a landscape scale. The abundance of T. heterophylla in the simulated landscape was particularly sensitive to variation in fire return interval and fire severity. T. heterophylla was less sensitive to canopy gap return interval, probability of recruitment in canopy gaps, and the probability of rare long-distance dispersal events. Relatively short periods of high fire frequency caused a rapid and persistent decline in the amount of T. heterophylla in the landscape. Based on the simulation results, we propose two new hypotheses. The first is that landscape-level constraints imposed by the frequency, severity, and pattern of wildfires will limit the potential for gap-level processes to affect T. heterophylla regeneration patterns at the landscape scale. The second, related hypothesis is that legacies of cumulative fire effects will have a strong influence on the subsequent development of late-successional forest structure.

    Publication Notes

    • You may send email to pnw_pnwpubs@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

    Wimberly, Michael C.; Spies, Thomas A. 2002. Landscape- vs gap-level controls on the abundance of a fire-sensitive, late-successional tree species. Ecosystems. 5: 232-243

    Keywords

    Tsuga heterophylla, western hemlock, fire, gap dynamics, seed dispersal, old growth, simulation, historical legacy

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page
https://www.fs.usda.gov/treesearch/pubs/24648