Stakeholder perceptions and scientific evidence linking wildfire mitigation treatments to societal outcomes.

A number of watershed partnerships have emerged in the western US to address the impacts of wildfire through investing in wildfire mitigation activities. To motivate collective action and design effective risk mitigation programs, these stakeholders draw on evidence linking wildfire mitigation to outcomes of interest. To advance knowledge in this area, we 1) assessed the strength of existing scientific evidence linking wildfire mitigation treatments with societal outcomes and 2) measured the importance of this evidence to watershed partnerships in the western US. To address objective one, we created a systematic evidence map to identify the most common wildfire mitigation treatment and societal outcome relationships reported. From the more than 100 studies examined, we found that the most commonly studied linkages were related to the impacts of thinning on infrastructure and timber. To answer objective two, we surveyed 38 professionals affiliated with organizations involved in eight watershed partnerships in the western US. We asked about the relative importance and strength of evidence linking wildfire treatments to societal outcomes for their watershed partnership, and used this information to create an importance-strength analysis and gap analysis. We found that most linkages were considered important to these organizations, and that the biggest gap identified was for evidence linking mulching to water quality or quantity outcomes. Forest and wildfire specialists perceived a larger need for additional evidence generation than other professional groups. Jointly, the results from this study point to areas of evidence generation important for watershed partnerships and other organizations involved in wildfire mitigation, and suggest a need to more thoroughly disseminate information about existing evidence to this new group of stakeholders investing in wildfire risk mitigation.

Return on investment from fuel treatments to reduce severe wildfire and erosion in a watershed investment program in Colorado.

A small but growing number of watershed investment programs in the western United States focus on wildfire risk reduction to municipal water supplies. This paper used return on investment (ROI) analysis to quantify how the amounts and placement of fuel treatment interventions would reduce sediment loading to the Strontia Springs Reservoir in the Upper South Platte River watershed southwest of Denver, Colorado following an extreme fire event. We simulated various extents of fuel mitigation activities under two placement strategies: (a) a strategic treatment prioritization map and (b) accessibility. Potential fire behavior was modeled under each extent and scenario to determine the impact on fire severity, and this was used to estimate expected change in post-fire erosion due to treatments. We found a positive ROI after large storm events when fire mitigation treatments were placed in priority areas with diminishing marginal returns after treating >50-80% of the forested area. While our ROI results should not be used prescriptively they do show that, conditional on severe fire occurrence and precipitation, investments in the Upper South Platte could feasibly lead to positive financial returns based on the reduced costs of dredging sediment from the reservoir. While our analysis showed positive ROI focusing only on post-fire erosion mitigation, it is important to consider multiple benefits in future ROI calculations and increase monitoring and evaluation of these benefits of wildfire fuel reduction investments for different site conditions and climates.