Prescribed fires are increasingly used in grassland management efforts throughout the Great Plains, but rarely do managers consider fire behavior when applying prescribed fire. Grassland fires can vary in their intensity and behavior, which could affect the ways in which plant communities respond to these fires. To quantify grassland prescribed fire behavior, we sampled 26 prescribed fires conducted at three study sites across North Dakota from October 2017 to October 2019. For each fire, we recorded weather conditions at ignition and quantified fuels and fire behavior with a system of 27 sample points nested at four spatial scales (fire event, 100 m, 10 m, and 1 m).
Results/Conclusions
Despite geographic and seasonal variation, fires were conducted during similar weather and fuel conditions across the three study sites. While fuel load and moisture were most heterogeneous at 1m scales, this did not translate to effects on fire behavior. Instead, fire behavior was most strongly determined by site characteristics. Our results suggest that current, conservative practices generate similar fires across our region despite obvious variation in fuel conditions. Furthermore, fire heterogeneity is more strongly determined by thermodynamics associated with the fires themselves and less as a result of site conditions. Future management efforts would be best directed toward managing fire behavior through different ignition styles and toward monitoring vegetation responses to fires of varying intensities.