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


    Thirteen-year growth response of ponderosa pine to various manipulations of understory vegetation was studied to determine if a threshold of understory cover can be established for plantation productivity and whether nitrogen-fixing Ceanothus species benefit plantation growth compared to non N-fixing Arctostaphylos species, given their ability to improve site fertility. Results showed that completely controlling competing vegetation increased plantation growth, as was universally expected, but the effects of partial shrub control on plantation performance was inconsistent. We did not find a benefit of nitrogen-fixing shrubs on tree growth, as young plantation growth was slightly better in the non N-fixing plots compared to the N-fixing plots due to differences in shrub cover. An understory cover threshold for tree growth was not observed. Due to the overriding effect of shrub competition, controlling herbaceous species had little effect on plantation growth even though it benefited tree seedling survival. A long-term value of N-fixing shrubs at these sites, if there is one, must be balanced by successful plantation establishment and rapid early growth.

    Publication Notes

    • You may send email to 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.


    Zhang, Jianwei; Busse, Matt D.; Fiddler, Gary O.; Fredrickson, Ed. 2020. Thirteen-year growth response of ponderosa pine plantations to dominant shrubs (Arctostaphylos and Ceanothus). Journal of Forestry Research. 31(4): 1445-1451.


    Google Scholar


    Competing vegetation control, manzanita, Nitrogen-fixing Ceanothus, Pinus ponderosa growth, shrub cover

    Related Search

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