The ultimate goal of this research is to provide a mechanistic understanding of surface fire behavior to increase managers’ ability to manipulate fire behavior during prescribed fire operations to meet ecological objectives in an effective, efficient, and safe manner on Department of Defense (DoD) lands. Ignition characteristics and vegetation heterogeneity are dominant controls over surface fire behavior and effects through their influence on: 1) local combustion characteristics; 2) ambient and fire-induced wind flow; and 3) heat transfer to vegetation. The research team will focus on characterizing spatially explicit and temporally resolved feedbacks among these factors using a novel combination of experimental and mechanistic modeling linked to fire effects through spatial analysis of heat transfer.

• Objective 1: Identify relationships between ignition characteristics and resulting spatially and temporally varying vegetative thermal environments (i.e., the magnitude and duration of heat flux) under a range of atmospheric conditions (local and plot scale) and fuel configurations.
• Objective 2: Provide a mechanistic explanation for the relationships observed in Objective 1, including description of cause and effect relationships, critical feedbacks, and sensitivity to ignition characteristics and environmental conditions (e.g., winds and fuel heterogeneity) using FIRETEC (short for the computation fluid dynamic coupled fire atmospheric model IGRAD/FIRETEC).
• Objective 3: Characterize dose-dependent fire effects of vegetative thermal environment on plant tissues and represent this characterization in a new modeling tool that predicts fire effects based on spatially explicit outputs of FIRETEC.
• Objective 4: Apply mechanistic insights and results from Objectives 1-3 above to test the spatially explicit fire behavior and fire effects predictions on operational scale prescribed fires representing actual management scenarios and additional fuel types.

The overall technical approach of this project includes four interrelated objectives. To meet these objectives, the research team proposes to utilize an iterative study design linking mechanistic modeling (FIRETEC) with multiscale empirical observations of prescribed burns to predict and test important sources of spatial variation in fire behavior. The research team will use spatial pattern recognition analysis to tailor field sampling, then incorporate field observations into hindcast models of burns. Future modeling and sampling design will be linked by this feedback to assess mechanisms responsible for variation in 3-dimensional energy transfer and subsequent fire effects throughout the project timeline. Iteratively applying and improving mechanistic predictions to experimental burns will allow the findings to extend beyond the conditions of the experiments, a critical limitation of current empirical approaches.

The long-term goal is to develop spatially explicit management tools that mechanistically link vegetation structure, fuels, fire behavior and fire effects. The focus on surface fire interactions is critical to DoD science needs. This work is the next step along a continuum of research that the team has been systematically pursuing for over 10 years through funding from a variety of sources, including DOD projects (RC-2641, RC-2243). Ultimately, it is the expectation that the completion of this project will result in novel knowledge and tools that will enhance fire and fuel managers’ ability to develop effective, efficient, and safe fire management strategies for DoD lands.