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Cattle play an important role in wildfire management by grazing fuel on California rangelands. The benefits of cattle grazing have not been thoroughly explored, though. Using statewide cattle inventory, brand inspection and land use data, we have estimated that cattle removed 11.6 billion pounds (5.3 billion kilograms [kg]) of non-woody plant material from California's rangelands in 2017. Regionally, these reductions varied between 174 and 1,020 pounds per grazed acre (195 to 1,143 kg per hectare). Fire behavior is characterized in this paper by flame length. Fire behavior models suggest that these regional fuel reductions lower flame lengths, and lead to more manageable wildfires. In addition, fire-based models show that cattle grazing reduces fuel loads enough to lessen fire hazards in many grazed areas. Moving forward, there may be significant opportunities to expand strategic grazing on rangelands to add extra layers of protection against wildfires. [ABSTRACT FROM AUTHOR]

Abstract: The recently developed method of chemical explosive mode (CEM) analysis (CEMA) was extended and employed to identify the detailed structure and stabilization mechanism of a turbulent lifted ethylene jet flame in heated coflowing air, obtained by a 3-D direct numerical simulation (DNS). It is shown that CEM is a critical feature in ignition as well as extinction phenomena, and as such the presence of a CEM can be utilized in general as a marker of explosive, or pre-ignition, mixtures. CEMA was first demonstrated in 0-D reactors including auto-ignition and perfectly stirred reactors, which are typical homogeneous ignition and extinction applications, respectively, and in 1-D premixed laminar flames of ethylene–air. It is then employed to analyze a 2-D spanwise slice extracted from the 3-D DNS data. The flame structure was clearly visualized with CEMA, while it is more difficult to discern from conventional computational diagnostic methods using individual species concentrations or temperature. Auto-ignition is identified as the dominant stabilization mechanism for the present turbulent lifted ethylene jet flame, and the contribution of dominant chemical species and reactions to the local CEM in different flame zones is quantified. A 22-species reduced mechanism with high accuracy for ethylene–air was developed from the detailed University of Southern California (USC) mechanism for the present simulation and analysis. [Copyright &y& Elsevier]