Pacific Southwest

Title: Initial response to understory plant diversity and overstory tree diameter growth to a green tree retention harvest

Author: North, Malcolm; Chen, Jiquan; Smith, Gordon; Krakowlak, Lucy; Franklin, Jerry

Date: 1996

Source: Northwest Science, Vol. 70(1): 24-35

Description: The increasing use of harvest techniques other than clearcutting in forests west of the Cascade mountains has created an urgent need to understand the effects of these practices on ecosystem species composition and structure. One common alternative, "green tree retention" (GTR), leaves some live trees on a harvest site to more closely mimic a moderate-intensity fire or wind disturbance. We examined the response of understory plant diversity and basal area increment of retained overstory trees after sixteen months and six years, respectively, in GTR cuts. Understory species cover was sampled on three adjacent treatment areas in the Seattle City Watershed, Washington: a clearcut, a dispersed green tree retention and the intact sixty-five year old forest. The change in basal area increment on dispersed green tree retention cuts was sampled with increment cores collected in six stands and two uncut control stands in the Wind River and H.J. Andrews Experimental Forests in Washington and Oregon, respectively. Herb and shrub species richness and evenness were significantly higher in the green tree retention cut than in the other two understory treatments. Although overall species composition of the GTR was closer to the clearcut than the forest, the GTR retained more species and cover of shade-tolerant plants important for maintaining understory diversity as canopy closure reduces understory light. While the basal area increment response of retained trees varied between stands, the average response for all stands for a six year period following harvest was a 15% reduction in increment growth compared to the control stands. Additional study is needed to determine the persistence of these effects and how basal area growth response varies as a function of tree size and age.

Keywords: 

View and Print this Publication (910 KB)

Pristine Version:  An uncaptured or "pristine" version of this publication is available. It has not been subjected to OCR (Optical Character Recognition) and therefore does not have any errors in the text. However it is a larger file size and some people may experience long download times. The "pristine" version of this publication is available here:

View and Print the PRISTINE copy of this Publication (1.1 MB)

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.

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

Citation

North, Malcolm; Chen, Jiquan; Smith, Gordon; Krakowlak, Lucy; Franklin, Jerry  1996.  Initial response to understory plant diversity and overstory tree diameter growth to a green tree retention harvest.   Northwest Science, Vol. 70(1): 24-35.