Effects of vegetation control treatments for release of Engelmann spruce from a mixed-shrub community in southern British Columbia – Year 15 results

Abstract

Fifteen-year results from a study initiated in 1992 to compare the effectiveness of repeated cutting treatments with treatments involving single cutting or a single application of glyphosate herbicide are presented. While treatments resulted in significant improvements in diameter and height of planted spruce at ages 3 to 7, these differences were no longer significant in year 15. All vegetation control treatments significantly increased survival in year 15 but did not significantly affect average spruce size. Despite apparent initial treatment effects on vegetation cover, the treatments applied in this study have had little lasting effect on non-crop vegetation. Key words: vegetation management, herbicides, glyphosate, manual, interior spruce, mixed shrub complex, Interior Cedar Hemlock Zone.