Analyzing impacts of brush saw and herbicide treatments on branching and stem quality in northern Ontario jack pine plantations

Abstract

In an industry where new science is ever-evolving, forest managers must constantly look towards research to guide best practices in achieving the highest quality forest product. Three common silvicultural treatments (aerial spray of Vision® herbicide, motor manual brush saw, and complete removal with repeated applications of Vision® herbicide) were used on two separate sites located in eastern and western Ontario. This study was conducted in order to determine the effect of both treatment and site (as well as the combination of the two factors) on both stem and branch quality of jack pine crop trees. When consideration of tree mortality was included in the analysis, it was found that aerial spray yielded best overall results for both branch and stem quality and that the difference in treatment means can be considered statistically significant (p < 0.05). When dead stems were removed from the analysis however, it was found that treatment type did not have a significant effect on stem quality. This did not remain true for branching quality, where tests of the remaining live trees showed a significant difference in values among the various treatments, with control providing best average branching quality scores. Finally, a significant difference was found to exist in stem quality between the two sites, with the E.B. Eddy site proving better average vales. Average stem mortality was also investigated, and it was found that the addition of herbicide treatments yielded better stem survival of the jack pine crop trees, with the worst average stem survival occurring in the untreated sites.