Conifer crown fuel modeling: Current limits and potential for improvement

The characterization of crown fuel parameters is a critical element in many fire behavior simulators used for decision support in the fire-prone coniferous forests of western North America. We briefly review the development and limitations of current conifer crown fuel models in this region as they impact the potential utility of fire behavior simulations. We then identify and evaluate conifer crown modeling efforts and techniques that have been advanced outside the fire and fuels domain, including models developed for bio-energy and carbon inventory, wood quality determination, and empirical and process-based growth and yield projections. Whereas the latter models often focus on crown parameters distinct from those traditionally described in fuels studies, we contend that advances in conifer crown fuel modeling can be made by recognizing and extending the results of these parallel lines of research. Such advances are needed to adequately parameterize crown fuels if we are to reap advantages from next-generation fire behavior models and, by extension, to improve our understanding of fuels management and treatment strategies. At the same time, more information must be derived from long-term fuels treatment and silvicultural trials to improve our understanding of how conifer crowns respond to treatments.