Skip to page content
USDA Forest Service

Research & Development Treesearch

Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help - We Participate  Government Made Easy

Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (187 KB bytes)

Title: Competitive Effects of Various Grasses and Forbs on Ponderosa Pine Seedlings

Author: Elliott, Katherine J.; White, Alan S.;

Date: 1987

Source: Forest Science. Vol. 33, No. 2, pp. 356-366 1987

Publication Series: Miscellaneous Publication

Description: Competition between ponderosa pine seedlings and various grasses and forbs was studied on :I site in northern Arizona burned in 1982 by a wildfire. Two-year-old pine seedlings were planted in 3.05 x 3.05 m plots in April 1983, followed by the sowing of grass and forb seeds on the same plots in July 1983 after summer rains had begun. Predawn xylem water potential of the pine seedlings was measured biweekly throughout the 1983 and 1984 growing seasons. Extractable soil nitrogen was measured at the beginning and end of both growing seasons. After the wildfire, nitrate and ammonium levels were significantly higher in the burned area than in an adjacent unburned area. Nitrate and ammonium concentrations in various grass treatment plots were significantly (P<0.05) different at both the beginning and end of the growing season. Pine seedling xylem water potential differed among treatments, with potentials being lowest on plots sown with Agropyron desertorum. The differences in seedling xylem water potential and available soil nitrogen were reflected in differences in pine seedling growth. The most effective competitors were Agropyron desertorum and Dactylis glomerata. Results indicated that competition occurred for both moisture and available nitrogen.

Keywords: competition, xylem water potential, nitrate, ammonium, Pinus ponderosa

Publication Notes:

  • 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.
  • 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.)



Elliott, Katherine J.; White, Alan S. 1987. Competitive Effects of Various Grasses and Forbs on Ponderosa Pine Seedlings. Forest Science. Vol. 33, No. 2, pp. 356-366 1987


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.