OREGON – Helping people find long-term solutions for natural resource problems is central to the work conducted by the Pacific Northwest Research Station. This often requires assembling and processing vast amounts of information and creating models that evaluate phenomena in the natural world. Some of these problems require new modeling tools to incorporate and evaluate new and complex data sources. These models are commonly referred to as decision-support tools.

The Lake Tahoe basin is a good example of a landscape in which high-value ecological and social outcomes hang in the balance as the climate changes over the next century. Recent climate assessments for California and the Lake Tahoe basin raised substantial concerns for the health and resilience of the forests, including their biodiversity, and the future of the renowned clarity of Lake Tahoe. The 2021 Caldor Fire, at more than 220,000 acres and still burning, has shifted the conversation from theory to reality. The fire burned into the western edge of the basin before being contained by the extraordinary efforts of firefighters and previous forest thinning projects.

To address these concerns, state, federal, university and local organizations came together to form the Lake Tahoe West Restoration Partnership. The goal of the partnership is to gain a better understanding of conservation options and to expedite selection of management actions to improve the resilience of forest ecosystems on the west side of the Lake Tahoe basin. As part of this effort, Keith Reynolds, PNW Research Station, and Eric Abelson, Pacific Southwest Research Station, developed a decision-support tool for the partnership to evaluate the performance of five alternative management strategies over the next 100 years. The decision-support tool considered the ecological, social and economic dimensions of ecosystem resilience.

The five modeled management scenarios selected by Lake Tahoe West Restoration Partnership were:

• Fire suppression only: No management other than suppressing natural or arson-caused fire.
• Wildland-urban interface focus: Forest thinning restricted to the WUI to provide defensible space around structures and private property. This scenario largely reflects current management practices in the Lake Tahoe basin.
• Forest thinning-based approach: Forest thinning expanded to areas outside the WUI by using mechanical methods to remove biomass.
• Fire-based approach: Forest thinning expanded to areas outside the WUI by using prescribed fire for one month per year.
• Intensive fire-based approach: Forest thinning expanded to areas outside the WUI with a more intense use of prescribed burning throughout the year.

Of the five modeled scenarios, the intensive fire-based approach most effectively met the identified goals. The strategy behind this scenario involved extensive application of prescribed and managed fire in the Lake Tahoe West subregion compared to strategies that were either less extensive or relied on mechanical treatment. The results, and the process that led to them, provide decisionmakers with insight into forest dynamics based on a rational, transparent and repeatable decision-support processes.

The ability to evaluate multiple natural resource and societal outcomes across unique future management scenarios is becoming an essential capacity to inform and support design of natural resources projects and planning decisions. However, decision-support tools that can incorporate large spatial extents, long time frames, multiple management scenarios and composite suites of resource and societal values are relatively rare and require specialized knowledge and skills to develop. Learn more about this project and this decision-support tool.