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 (156 KB)

Title: Understory cover and biomass indices predictions for forest ecosystems of the Northwestern United States

Author: Suchar, Vasile A.; Crookston, Nicholas L.;

Date: 2010

Source: Ecological Indicators. 10: 602-609.

Publication Series: Scientific Journal (JRNL)

Description: The understory community is a critical component of many processes of forest ecosystems. Cover and biomass indices of shrubs and herbs of forested ecosystems of Northwestern United States are presented. Various forest data were recorded for 10,895 plots during a Current Vegetation Survey, over the National Forest lands of entire Pacific Northwest. No significant relationships between the percent canopy cover and understory percent cover and biomass indices were found for the 129 ecoclasses analyzed. Disturbance time and type, and the soil characteristics significantly influenced the shrub biomass indices (p-values of <0.001, <0.001, and 0.01, respectively). Only disturbance time and type significantly influenced the shrub percent cover (p-values <0.001). There were no significant interactions between these variables. No significant differences were found for herb biomass indices and cover. Climate variables are reasonable predictors of understory cover and biomass indices. Elevation and slope are also influential: understory cover decreases with altitude, while understory biomass increases with slope. Most models showed weak predictive power (adjusted R-squared ≤0.27). However, robust models for the maximum/potential understory biomass indices for the forested areas in the Northwestern United States are reported (adjusted R-squared of 0.76 and 0.51 for shrubs and herbs, respectively). Overall, our study provides conceptual and statistical models for the understory of the National Forest lands of the Pacific Northwest. The results are comparable with other models for the area, suggesting that the predictions regarding understory vegetation are inherently difficult.

Keywords: understory cover and biomass, Pacific Northwest, understory­overstory relationship, understory­climate relationship

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.



Suchar, Vasile A.; Crookston, Nicholas L. 2010. Understory cover and biomass indices predictions for forest ecosystems of the Northwestern United States. Ecological Indicators. 10: 602-609.


 [ 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.