Advancing the Science of Wildland Fire Dynamics Using Process-Based Models

Abstract

As scientists and managers seek to understand fire behavior in conditions that extend beyond the limits of our current empirical models and prior experiences, they will need new tools that foster a more mechanistic understanding of the processes driving fire dynamics and effects. Here we suggest that process-based models are powerful research tools that are useful for investigating a large number of emerging questions in wildland fire sciences. These models can play a particularly important role in advancing our understanding, in part, because they allow their users to evaluate the potential mechanisms and interactions driving fire dynamics and effects from a unique perspective not often available through experimentation alone. For example, process-based models can be used to conduct experiments that would be impossible, too risky, or costly to do in the physical world. They can also contribute to the discovery process by inspiring new experiments, informing measurement strategies, and assisting in the interpretation of physical observations. Ultimately, a synergistic approach where simulations are continuously compared to experimental data, and where experiments are guided by the simulations will profoundly impact the quality and rate of progress towards solving emerging problems in wildland fire sciences.

Fine‐scale fire patterns mediate forest structure in frequent‐fire ecosystems

“…Plant tissue damage and mortality are the direct result of complex, three‐dimensional heat transfer processes the quantification of which represents an important frontier in the understanding and prediction of fire effects on plant and ecosystems (O’Brien et al 2018). Spatially explicit, physical models such as the one used here are powerful tools that will play an integral role in progress on this frontier (Hoffman et al 2018, Yedinak et al 2018). Through a detailed analysis of the interactions between spatial pattern and heat transfer, we show fine‐scale pattern‐process linkages whereby the local arrangement canopy fuel surrounding a tree alters its risk of torching and consumption due to changes to net convective and radiative heating.…”

“…While simulating a free‐spreading surface fire through spatially heterogeneous fuels is possible in WFDS‐PB, this simplification allowed us to assess the effect of group size and tree separation distance under consistent heat exposure conditions and to replicate the surface fires reported in Van Wagner (1968). The ability to isolate the effects of specific variables or processes on ignition and consumption represents a significant benefit of using a physical model like WFDS‐PB as it would physically impossible to separate variables like surface and canopy fuels in the real world (Hoffman et al 2018). Although our surface fire intensity, spread rate, and depth were held consistent throughout a simulation, it is important to note that the fire plume, which is the source of a tree's heat flux exposure, was not constrained and evolved according to the interactions among the buoyant flow, the tree crown(s) and ambient wind.…”

A response to ‘Clarifying the meaning of mantras in wildland fire behaviour modelling: reply to Cruz et al. (2017)'

“…We agree that physical-based modelling, underpinned by sound experimental evidence and interpretation, will contribute to our understanding of fire propagation processes (Hoffman et al 2018). We are in fact on record as having said that physical models hold great promise (Sullivan 2009b(Sullivan , 2009cAlexander and Cruz 2013a).…”

Stem-Maps of Forest Restoration Cuttings in Pinus ponderosa-Dominated Forests in the Interior West, USA

“…We then used the individual tree locations and their individual geometries as inputs to a physics-based fire behavior model. The Wildland-urban interface Fire Dynamics Simulator (WFDS) model is interoperable with stem-map data, as WFDS resolves the distribution of vegetative fuel throughout three-dimensional space [11]. The dual assessment of tree pattern manipulation and spatial tree-fire behavior interactions is important considering how much remains unknown regarding how tree spatial arrangements alter wildland fire behavior [6,12,13].…”