Long-term fire effects on vegetation structure on fire behavior in Wyoming big sagebrush

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This study sampled 17 years following prescribed fire in 4 burned and 4 unburned plots at Hart Mountain National Antelope Refuge, OR. Fuels data were used to model potential fire behavior in burn and control plots across four environmental scenarios that mimic drying of fuels through the fire season. Herbaceous fuels were 5 times greater in burns (P < 0. 01). Shrub fuel was nearly 10 times higher in unburned plots (P < 0.01), and litter under shrubs in controls was 3.75 times greater than in burns (P < 0.01). Potential fire behavior was lower in burned plots than in unburned controls across all environmental scenarios. In the driest scenario, potential rate of spread ranged from 0.4 to 1.5 m min⁻¹ in burns and 2.7 to 5.5 m min⁻¹ in controls (P < 0.01). Maintaining resilience in these ecosystems at multiple spatial and temporal scales may include a consideration of the natural role of fire in good condition Wyoming big sagebrush ecosystems. This study shows that under these conditions, fire can promote good condition mid-successional ecosystems and can act as a fuel break, slowing the spread and decreasing the intensity of a future wildfire.