OOS 23-7 - Ecologically relevant measurements of fire behavior for understanding fire effects

Wednesday, August 9, 2017: 10:10 AM
Portland Blrm 257, Oregon Convention Center
Benjamin S. Hornsby1, Joseph J. O'Brien1, E. Louise Loudermilk1 and Scott Pokswinski2, (1)Southern Research Station, Center for Forest Disturbance Science, USDA Forest Service, Athens, GA, (2)Department of Biology, University of Nevada, Reno

The ability to better understand the impacts of wildland fire on the natural environment requires a comprehensive knowledge of the behavior of the fire itself in addition to the direct and indirect effects post-fire. Investigations on fire effects typically involve measurements only the resulting conditions after the fire event or rudimentary measurements of fire behavior. Efforts to understand the fire environment have historically been attempted using various techniques that provide either an index of fire intensity or a series of temperature point measurements (°C). While temperature can provide an index of fire intensity it does not explain the transfer of energy from the combustion of material and the effects of that reaction on the surrounding environment. Within the past decade sensors that provide spatially explicit high resolution measurements of infrared radiation have become more reliable and available. A subset of these sensor packages detect the infrared energy emitted from a surface. The combination of the energy emitted from the object of interest during the combustion and optical properties of the sensors allow the images to be converted into a high resolution map temperature or the energy impinged on the object through time.


In this project, these techniques were used to bridge the gaps between the fire environment, the fuels and the associated changes in plant communities through time. Nadir high resolution infrared measurements were collected on 27 plots across two forest community types and stratified by canopy characteristics for two burn rotations. The stratification of plots across canopy densities generated a measurable link to surface fuels on a much larger scale. These same measurements were collected for an additional 9 plots where surface fuels were manipulated (addition of pine cones) to better understand the effects of energy released from the longer duration combustion of woody fuel types and how that directly affected mortality of neighboring plant species and created potential for recruitment of new ones. The ability to spatially capture the infrared energy emitted through time allowed for a much better understanding of the principle mechanism (energy transfer through combustion) altering plant communities and an enhanced understanding of the fundamental mechanisms that alter plant communities, their assembly and ultimately biodiversity.