Mechanical fuel reduction treatments: Constraints and opportunities for Wildfire Crisis Strategy landscapes

The Wildfire Crisis Strategy prioritizes 21 landscapes where wildfire poses the greatest threat to at-risk communities, water supply, and other values for fuel reduction treatment projects. The strategy seeks to treat 20-40% of the “high-risk” acres in the 21 landscapes over the next decade. However, increasing the scale of hazardous fuel reduction treatments may need to look different than the business-as-usual approach.

In a new analysis, researchers determined the extent and spatial arrangement of areas that are available for mechanical treatment operations and areas with operational or administrative constraints. Their results show that in order for the Forest Service to accomplish their Wildfire Crisis Strategy treatment objectives and to facilitate more widespread use of fire as a management tool, some of the priority landscapes may need to adjust their approach to mechanical fuel reduction treatment operations.

In support of the Wildfire Crisis Strategy implementation, this webpage provides a summary of the results and key findings around constraints and opportunities for conducting mechanical fuels reduction treatments for each of the 21 landscapes.

The Results by Landscape tab contains reports for each individual priority landscape that compile and summarize information with respect to meeting the Wildfire Crisis Strategy treatment objectives at the landscape level.
 

Photo Credit

Woolsey et al. 2024

The Forest Service's Wildfire Crisis Strategy prioritizes 21 landscapes for fuel reduction treatments in Arizona, California, Colorado, Idaho, Nevada, New Mexico, Montana, Oregon, Utah, and Washington. Ten landscapes outlined in black and 11 outlined in navy blue represent 2022 and 2023 Strategy investments, respectively. Firesheds within priority landscapes that were identified in the Strategy as areas with the highest risk to communities and resources are shaded red (multiple ownerships) and orange (Forest Service ownership only).

Methods

The research team delineated the areas within each Wildfire Crisis Strategy landscape that have operational and administrative constraints to conducting mechanical fuel reduction treatments. Their analysis used readily available datasets in a Google Earth Engine workflow to quantify the amount and spatial arrangement of land available for mechanical fuel reduction treatments after considering operational constraints within the 21 landscapes prioritized in the Wildfire Crisis Strategy. The team developed standardized criteria and a hierarchy of constraints to determine whether mechanical equipment was allowed and operationally feasible – as shown in the figure below. 

Photo Credit

George Woolsey, Colorado State University

Workflow used to quantify the amount of land available for mechanical forest health and risk reduction fuel treatments by considering layered operational constraints. This example illustrates (A) a fireshed project area near Rustic, Colorado in the Colorado Front Range priority landscape. The analysis identifies (B) all forest and shrubland areas, (C) removes protected and inventoried roadless areas, (D) classifies land as mechanically operable based on terrain slope, (E) buffers existing roads according to equipment haul distances, (F) removes areas within riparian buffers, (G) removes areas within administrative boundaries, and (H) determines what land is mechanically available or constrained and by what factor.

Some constraints, such as areas with slopes that are generally considered too steep for traditional treatment methods, areas with limited road access, and administrative reserves such as riparian areas and sensitive species habitat, could be overcome with increased funding, technological innovation, policy changes, or a combination thereof. Other constraints to treatment, such as designated wilderness areas where managers face legal limitations to the use of mechanical equipment, afford little flexibility to expand mechanical operations. The analysis focused on constraints that have some flexibility to overcome. 

Constraint Scenarios

To help managers identify potential pathways to meet the Wildfire Crisis Strategy and local objectives, the research team developed three (3) scenarios to represent a gradient in funding, policy, and management options for mechanical fuels reduction treatments.

• Scenario 1 reflects a status quo approach to mechanical treatments based on Forest Service operations in recent years. Under this approach, mechanical treatments occur on slopes <40% within 1,000 feet (305 m) of existing road infrastructure and are excluded within 100 ft (30 m) of waterways and all specialty administrative designations (e.g., sensitive species habitat, conservation areas, wildlife refuges).
• Scenario 2 represents a management approach characterized by increased investment to overcome physical constraints by working on steeper slopes up to 60% and increasing the use of temporary roads by extending the distance to existing roads to 2,000 feet (610 m). This scenario emphasizes utilizing recent innovations in mechanized harvesting systems, such as tethered or cable-assisted equipment, that have been designed to operate on steep slopes (e.g., 40%–60%) and may extend mechanical management opportunities to previously inoperable areas.
• Scenario 3 is the most thorough approach considered for expanding fuel reduction treatments in this analysis and builds on Scenario 2 by expanding treatment near riparian areas and within administratively designated areas. Management Scenario 3 represents a treatment approach that is characterized by both increased investments to overcome physical constraints (as in Scenario 2) and reduced administrative hurdles to implement treatment within reserved lands.

More information on the analysis, data sources, and study limitations can be found in the published work:  Constraints on mechanical fuel reduction treatments in United States Forest Service Wildfire Crisis Strategy priority landscapes. Although this analysis uses rigorous methods, it is not possible to account for all locally relevant social, economic, and environmental factors.