Modeling Ignition and Burning Rate of Large Woody Natural Fuels

Abstract

As part of the development of a model for predicting fuel loading reductions by and intensity histories of fires burning in large woody natural fuels, it was necessary to develop separate models for the processes of ignition and rate of burning of individual fuel elements. This paper describes the derivation of predictive equations for ignition delay time and burning rate (from diameter reduction rate) of large woody natural fuels in a fire environment. The method consists of deriving approximate functional forms using fuel component properties and a measurable ''fire environment temperature'' and then fitting these forms to data taken in laboratory fires using a large propane burner. The equations describe the calibration data with precision adequate for the purpose for which they were designed.

Wildland fire in ecosystems: effects of fire on soils and water

“…One problem with using current fire behavior prediction systems in ecological studies is that they focus on flaming combustion of fine fuels and do not predict all of the combustion and fuel consumned, or quantify all of the energy released, during a fire (Johnson and Miyanishi 2001). The intensity of residual combustion of large woody fuels is modeled in the BURNUP Model Reinhardt 1995, Albini andothers 1996) and the energy release rate from duff consumption is modeled in the First Order Fire Effects Model (FOFEM) v.5.0 (Reinhardt 2003).…”

“…Here flaming combustion may last a few hours resulting in substantial soil heating (Hartford and Frandsen 1992). However, the surface area occupied by long-burning woody fuels is typically small, less than 10 percent and often much less (Albini 1976, Ryan and Noste 1985, Albini and Reinhardt 1995. If canopy fuels are plentiful and sufficiently dry, surface fires begin to transition into crown fires (Van Wagner 1977, Scott and.…”

“…Depth of burn is directly related to the duration of burning in woody fuels (Anderson 1969, Albini andReinhardt 1995) and duff (Frandsen 1991a, 1991b, Johnson and Miyanishi 2001. In heterogeneous fuels, depth of burn can vary substantially over short distances (for example, beneath a shrub or tree canopy versus the inter-canopy area, or beneath a log versus not (Tunstall andothers 1976, Ryan and.…”

Fire behaviour and severity in a maritime pine stand under differing fuel conditions

“…V) and, as mentioned before, this might have been true for fuel properties not examined in this study. Such differentiation naturally led to a distinct history of heat release rate [4] with potential implications in the development of crown fire. However, and similarly to crown flame length, the plot effect should also comprise a crown fuel component, and the results are consistent with the theory of Van Wagner [62] which relates persistent fire propagation in the canopy to higher values of foliar bulk density.…”

Current status and future needs of the BehavePlus Fire Modeling System

“…1, Table 1), deficiencies would be addressed by incorporating new or improved models. For example, it would be worthwhile to add the large fuel burnout model which is currently in FARSITE and FOFEM, to model post-frontal combustion for fuel consumption and smoke production and to characterise intensity of more than the flaming front for modelling scorch height and transition to crown fire (Albini and Reinhardt 1995;Finney et al 2003).…”