Research Branch

See below to download.

Pinchi Lake Operational Herbicide Monitoring: 10-year Conifer and Vegetation Responses in the SBSdw3

Author(s) or contact(s): B.S. Biring, H.K. Yearsley, and W.J. Hays-Byl
Source: Research Branch
Subject: Vegetation Management
Series: Extension Note
Other details:  Published 2000. Hardcopy is available.


In forestry, vegetation management treatments are widely used to enhance establishment of young stands and achieve free growing requirements. In 1988, an operational herbicide monitoring trial was established in a 4-year-old white spruce (Picea glauca) and Douglas-fir (Pseudotsuga menziesii) plantation in the SBSdw3 biogeoclimatic zone to examine the effectiveness of glyphosate herbicide on a vegetation community. The study consists of two 1 ha treatment plots, one of which was treated with glyphosate once using a backpack sprayer at a rate of 1.8 kg a.i./ha. Ten years after treatment, glyphosate had increased basal diameter and crown radius, reduced height-to-diameter ratio, and improved vigour of white spruce. Fourteen years after planting, the glyphosate treated plot had significantly greater number of free growing spruce per ha. The treatment also increased conifer and herb percent cover, and reduced broadleaf and shrub percent cover. However, the treatment did not affect the plant species richness. Yield projections for conifers and broadleaves based on MGM suggest that treatment applied to control broadleaves and shrubs has the potential to increase conifer yield and reduce conifer rotation age.

Download Extension Note 46 PDF file (435 KB)

To view this document you need the current version of
Adobe Acrobat Reader, available free from the Adobe Web Site.

Updated April 19, 2007