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 (7.9 MB)

Title: Stand-level gas-exchange responses to seasonal drought in very young versus old Douglas-fir forests of the Pacific Northwest, USA

Author: Wharton, Sonia; Schroeder, Matt; Bible, Ken; Falk, Matthias; Paw U, Kyaw Tha;

Date: 2009

Source: Tree Physiology. 29: 959-974

Publication Series: Scientific Journal (JRNL)

Description: This study examines how stand age affects ecosystem mass and energy exchange response to seasonal drought in three adjacent Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. The sites include two early seral (ES) stands (0 to 15 years old) and an old-growth (OG) (~450 to 500 years old) forest in the Wind River Experimental Forest, Washington, USA. We use eddy covariance flux measurements of carbon dioxide, latent energy, and sensible heat to derive evapotranspiration rate, Bowen ratio, water use efficiency, canopy conductance, the Priestley-Taylor coefficient, and a canopy decoupling factor. Despite different rainfall patterns in 2006 and 2007, we observed site-specific diurnal patterns of evapotranspiration rate, Priestley-Taylor coefficient, canopy conductance, vapour pressure deficit, and relative soil water content during both years. Our results suggest that ES stands are more likely than mature forests to experience constraints on gas exchange if the dry season becomes longer or intensifies because water-conserving ecophysiological responses were observed in the youngest stands only at the very end of the seasonal drought.

Keywords: AmeriFlux, canopy conductance, eddy covariance, evapotranspiration, the Priestley-Taylor coefficient, Pseudotsuga menziesii, Wind River

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.



Wharton, S.; Schroeder, M.; Bible, K.; Falk, M.; Paw U, K.T. 2009. Stand-level gas-exchange responses to seasonal drought in very young versus old Douglas-fir forests of the Pacific Northwest, USA. Tree Physiology. 29: 959-974.


 [ 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.