Review of herbicide use for forest management in Alberta, 1995–2009

Abstract

This report reviews herbicide use for forest management purposes in Alberta between 1995 and 2009. Data for this review are drawn from the National Forestry Database, Government of Alberta records, anecdotal review of herbicide activities from participants, and the published literature. Alberta moved toward operational use of herbicides for forest management in a carefully monitored, step-wise process, with full adoption occurring in 2001–2002. Stakeholder engagement processes and the development of operational guidelines for risk identification and mitigation are described. A metric (Herbicide Excursion Intensity) has been developed and used to assess risk identification and mitigation efficiency independent of extent of herbicide use. Review of the temporal trends in this metric demonstrates that identification and mitigation of this element of risk associated with forest herbicide use in Alberta has been generally successful following initial learning experiences. Factors contributing to Alberta’s success in risk mitigation are: use of helicopters for all aerial application of forestry herbicides, adoption of drift control (AccuFlow™) nozzles, and quantitative prediction of spray cloud behavior in the Ag-Drift and SprayAdvisor models allowing gaming of weather conditions, buffer widths and nozzles to develop integrated risk mitigation processes. The report provides several recommendations, including the development of a Vegetation Management Strategy, to more explicitly link forest herbicide use with forest management planning.