Productivity, cost, efficacy and cost effectiveness of motor-manual, mechanical, and herbicide release of boreal spruce plantations

Abstract

Although the release of spruce plantations with herbicides is an important part of Ontario's reforestation program, the people of Ontario do not support the use of any pesticides in the forest environment. Of the available alternatives, those most feasible for conifer release in northern Ontario appear to be cutting with brush saws and using mechanized cleaning machines. In this study, a component of the Fallingsnow Ecosystem Project, we quantified the relative productivity, costs, treatment efficacy and cost effectiveness of: 1) motor-manual cutting (brush saws), 2) mechanical brush cutting (Silvana Selective/Ford Versatile), 3) helicopter application of Release® (a.i. triclopyr) herbicide, and 4) helicopter application of Vision® (a.i. glyphosate herbicide and compared these to control (untreated) plots. Productivity (productive machine hours ha−1) was lowest for brush saws, followed by Silvana Selective and highest for helicopter operations. Treatment and super-vision costs ($ ha−1) were highest for Silvana Selective, followed by brush saw, Release®, and lowest for Vision®. One year post-treatment, vegetation indices (percent cover × mean height) for non-conifer woody plants decreased in the Vision®, Silvana Selective, Release®, and brush saw treatments respectively and increased on control plots. Vegetation indices for herbaceous plants were lowest for Vision®, followed by brush saw, Silvana Selective, control and highest for Release® plots. The average cost effectiveness ratio was lowest for Vision®, followed by Release®, Silvana Selective, and highest for brush saws. As empirical data from the project becomes available, longer-term economic evaluations will be made. Key words: clearing saws, cleaning, conifer release, cost effectiveness, Fallingsnow Ecosystem Project, glyphosate, herbicides, machine evaluation, productivity, Release®, Silvana Selective, triclopyr, forest vegetation management, Vision®