Optimizing Weed Management in Forested Ecosystems

The Weed Control Act and Weed Control Regulation were developed to be protective of agricultural lands. The risk weed species pose to forest development is less understood, so there may be opportunity to approach weed management differently when the end land use is a forested ecosystem. This could lead to a reduction of herbicide use in forest ecosystems, which can have unintended negative effects on the environment, and reduce weed management costs. A survey and workshop were used to engage key stakeholders to: (1) understand how noxious weed management is currently implemented and enforced in forested ecosystems in Alberta; (2) identify alternate approaches to noxious weed management in these areas; (3) develop recommendations for a broadened interpretation of “control” that can be supported by multiple stakeholder groups; and (4) assess the need for empirical evidence and identify research gaps. 40 people from industry, government, consulting and academia answered the survey, and 21 people from industry, government, consulting and weed management services participated in the workshop.

Key Messages: (1) research and monitoring to date suggests common noxious weeds in the boreal region are not having long-term effects on establishment and growth of desired species and achievement of return to forested habitat; collection and compilation of additional data would strengthen the case for change; (2) there is a need to better understand when weed management should occur; is there a threshold weed density beyond which active management is needed?; (3) changes could be made to policy to better describe intent of weed control and ensure all sectors treated equitably. This approach needs to be in a government document (Guide or Policy), backed up by training of service providers, government decision makers and industry managers. A Best Management Practices (BMP) noxious weeds document is recommended, along with research to strengthen BMPs over time. Both the BMPs and the future work fall into these areas: (1) trade-offs between active (herbicide/manual removal) and passive weed management approaches; (2) thresholds in noxious weed abundance that would trigger need for active management; (3) trajectories of noxious weed development on reclaimed industrial site associated with timely succession to forest species; and (4) use of other weed management approaches to reduce weed establishment.