New perspectives in forest invader management for a resilient North American canopy

Background/Question/Methods

Healthy forests are key to supporting resilient ecological communities, human health and wellbeing, and many peoples’ livelihoods. While there have been recent calls for tree planting in both Canada and the United States, a nuanced approach to forest health beyond increasing tree quantity is necessary to effectively support forests, including limiting the impacts of forest invaders. Forest invader management is a domain that spans epistemologies, levels of government, and fields of academia. We sought to improve communication across these subdomains, especially considering forest management’s ever-evolving set of tools and its complex ecological, social, and biocultural contexts. We organized a survey and workshop to develop a contemporary, evidence-informed set of management best practices across all steps of the forest invader management response with experts across fields, including Indigenous knowledge holders, government scientists, NGO employees, and academics. We first contacted these experts to solicit preliminary themes, tactics, and concepts in forest invader management, which we used to create a survey to rank priorities and add missing themes. We then spent a two-day workshop developing the major themes that emerged in the survey and summarizing them by their relative feasibility and novelty in light of their known tactics.

Results/Conclusions

Dominant themes included the need for decision support tools to balance tradeoffs among the social, ecological, and economic consequences of invasions and their management, scenario models of inaction versus action in the face of invasions, and increased understanding of the effects of climate change on invader impacts. Participants highlighted several barriers to proactive, two-way communication concerning invasive species management decisions among and within municipalities, Indigenous communities, governments, and academics, including the separation of management responsibility among agencies and limited capacity in smaller communities. Participants also stressed the need to make space for Indigenous knowledge within invasive species management, including respecting different paradigms within which to understand species invasions, and the need to correct the lack of historical and present engagement of Indigenous peoples in forest management on their lands. Participants further noted several examples of communication failures and biases preventing the acceptance of certain technologies such as biological control. We illustrate our findings using two case studies of past management successes and failures: the history of Asian longhorned beetle management, and new empirical data on Canadian border interceptions of infested wood and wood products from 1989-2020.