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 1-year-old white spruce (Picea glauca) 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 aerially applied glyphosate at a rate of 2.14 kg a.i./ha. Ten years after treatment, glyphosate had increased height and basal diameter, reduced height-to-diameter ratio, and improved vigour of white spruce. Eleven years after planting, the glyphosate treated plot had significantly greater number of free growing spruce per ha, and significantly less percent cover and density of broadleaves than the untreated control plot. However, the treatment did not affect the plant species richness. Yield projections for white spruce an trembling aspen based on MGM suggest that treatment applied to control broadleaves and shrubs has the potential to increase conifer yield and reduce conifer rotation age.
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Updated April 19, 2007