USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

1731 Research Park Dr.
Davis, CA 95618
(530) 759-1700
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Fire Science

Masticated Fuels:
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Masticated Fuels

Masticated fuels along Taylor Ridge, Klamath National Forest.


Dense flammable vegetation and seasonally extreme fire weather present a daunting fuels management challenge in the foothill and mountain regions of California and southern Oregon. Much of this area historically burned in relatively frequent low to moderate severity fires, helping to thin the forest understory and reduce the potential for severe wildfires. Fire suppression, past management practices, and unusually severe wildfires have all contributed to the dense thickets of shrubs and small trees common in many areas today. Prescribed fire is one means of reducing wildfire hazard, but risks associated with the proximity to homes, air quality issues, and the lack of prescription burning opportunities limit its use. Treatment of shrub and small tree fuels with mechanical mastication is one alternative. When we started the project little was known about the effectiveness of mastication for altering fire behavior, and about the fire behavior and fire effects of burning masticated fuel beds.

In order to address some of the unknowns, researchers with the U.S. Forest Service Pacific Southwest Research Station, Humboldt State University, and Mississippi State University began looking at fire effects from burning masticated fuels. Early work resulted in a paper showing the potential for substantial soil heating when masticated fuels are burned (Busse et al. 2005). The research was later expanded with funding from the Joint Fire Science Program (JFSP) (2005 to 2008). With new funding from JFSP (2013 to 2015), we will revisit masticated sites from the first phase of research and additional sites with varying treatment history to evaluate surface and live fuel succession over time, and determine how decomposition of masticated residues influences potential fire behavior.