Researchers Bolster Wildfire Crisis Strategy with Forest-Restoration and Fuel-Treatment Study

To ensure the success of the agency’s 2022 10-year Wildfire Crisis Strategy, Forest Service researchers are working on an innovative new project to provide information about fuel-treatment effectiveness and long-term ecological responses on priority landscapes.

Forest restoration and fuel reduction treatments are key management strategies to reduce wildfire risk and foster forest resilience to future fires and a warming climate. The combination of mechanical thinning followed by prescribed fire is generally recognized as the most effective approach for reducing fuels and fire hazards in degraded dry coniferous forests.

Photo Credit

USDA Forest Service photo by Jason Emhoff.

The Canteen Prescribed Fire in the Okanogan-Wenatchee National Forest, pictured here, supports the USDA Forest Service’s Wildfire Crisis Strategy to mitigate fire risks to communities and create landscapes that are more resilient. Burning occurred in spring 2023 in a high-risk fireshed near the communities of Nile and Naches, Washington. 

However, a better understanding of how and where treatments are likely to be most effective is needed. Also, the longer term effects of fuel reduction and forest restoration treatments are not well understood.

Research forester Dave Peterson and ecologist Kathryn Ireland, both with the Pacific Northwest Research Station, will be evaluating treatment longevity in forests of varying site productivity, initial stand structure, and disturbance histories to generate better understanding of how treatment longevity varies within forest landscapes.

Although forest restoration treatments have been widely applied to mitigate wildfire hazard, their long-term interaction with climate variability, drought, and other subsequent disturbances remain poorly understood. This project will help provide better understanding of how thinning treatments interact with drought, climate, and disturbance, ultimately making it easier to assess the long-term ability of these treatments to promote forest resilience.

Researchers will collect wood samples from trees across a wide range of climatic conditions, treatment, and disturbance histories. By analyzing the tree rings, the research team will be able to assess how different treatments effected tree growth rates and sensitivity to drought and climate variability.

Objectives

• Assess the short-term effectiveness of forest restoration and fuel reduction treatments for altering forest fuel profiles, restoring stand structure to desired conditions, and reducing wildfire hazards across a range of pretreatment forest types and successional stages based on empirical data from field studies. 
• Assess the long-term effects of forest restoration and fuel reduction treatments on forest fuel profiles, overstory stand structure, wildfire hazard, and forest regeneration across a range of fuel treatments, forest types, and climatic settings based on empirical data from field studies. 
• Assess the effects of stand density management (e.g., thinning treatments) and other disturbances (e.g., wildfire and insects) on tree growth rates and growth responses to climate using the systematic study of ecological and environmental effects on tree ring growth. 
• Develop the capability to probabilistically model changes in forest structure, forest fuels, and fire hazards during and following restoration and fuel treatments by adapting and validating a multiscale, process-based, tree-growth simulation model (iLand) for use with interior dry coniferous forests of the Pacific Northwest.

Expected Products

The results of this research will be communicated through written publications (refereed journal articles or agency publications), oral presentations, and field tours. A capstone published report and project website will summarize field research results, model outputs, and contributions to management processes and outcomes.

Expected Outcomes

This study will (1) improve our knowledge about long-term forest responses to restoration and fuel reduction treatments that involve forest thinning and prescribed fire; (2) provide information needed to anticipate future treatment maintenance needs; (3) refine and test a multiscale, process-based model to project management treatment outcomes decades into the future under different climate and management scenarios; and (4) assist managers in prioritizing treatments based on long-term data and predicted outcomes.

An integral part of this project involves developing a coproduction relationship among the project teams at the Pacific Northwest Research Station’s Wenatchee Forestry Sciences Laboratory, the University of Washington, and the Okanogan-Wenatchee National Forest. The research team will work closely with partners to identify research priorities, select representative forest restoration treatments to study, develop relevant management scenarios for modeling, and disseminate research results.

Metrics of Success

The project will be successful if (1) researchers and managers develop a successful coproduction relationship to design realistic management scenarios for predictive modeling; (2) initial and persistent effects of fuel and restoration treatments are communicated to coproduction partners and disseminated to managers within the priority landscape in central Washington; (3) the iLand tree-growth simulation model is successfully parameterized and applied to the priority landscape, and (4) workshops or meetings are held with coproduction partners to discuss how empirical data and model predictions can be incorporated into their management planning.

Keywords: Forest restoration, fuel treatment, wildfire crisis priority landscape, coproduction, BIL.