Fuel breaks: ecosystem benefits and risks

Increasing drought and the spread of invasive annual grasses throughout the American West are causing more frequent wildfires across the sagebrush biome. Land managers use fuel breaks to suppress wildfire and protect healthy, resilient sagebrush ecosystems. The overall ability of fuel breaks to meet these goals depends on a variety of factors, including local soil conditions, their distance to important wildlife habitat, the number of other fuel breaks in the area, and the accessibility of the fuel break to fire crews. However, in some cases, the risk of constructing a fuel break may outweigh its benefits: for instance, fuel breaks may facilitate invasive species spread or degrade important wildlife habitat.

Sagebrush ecosystems contain approximately 10,000 km of fuel breaks – about twice the length of the continental United States – but until recently, their locations were not broadly available. In this study, researchers synthesized data on fuel break location with ecological data like burn probability, fuel break effectiveness, invasive annual grass cover, and locations of important wildlife habitat (Roche and others, 2024) to learn more about the ecological trade-offs of fuel breaks in sagebrush ecosystems.

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The net benefits of fuel breaks vary greatly across the sagebrush biome

Researchers found that, across the sagebrush biome, most fuel breaks were accessible to fire crews, and were generally located in areas of high burn probability. However, they were more likely to be in locations with low predicted fuel break effectiveness, and were often spatially associated with areas of high invasive grass cover. In addition, there were dense fuel break networks within priority wildlife areas, potentially intercepting more wildfires and reducing wildfire spread, but also potentially fragmenting and degrading critical wildlife habitat. In all, individual fuel breaks varied widely in their risk-benefit profiles across the biome (see Figure).

Management implications

Results of this study highlight the need for careful evaluation of both the potential benefits and risks of fuel breaks for ecosystem conservation. Additionally, managers can use the data compiled in this study to weigh the pros and cons of future fuel break management actions.