A stochastic fire spread model for north Patagonia based on fire occurrence maps

MORALES, J.M.; KITZBERGER, T.; GOWDA, J.H.; MERMOZ, M.

ECOLOGICAL MODELLING

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 300 p. 73 - 80

0304-3800

tUnderstanding fire spread in different ecosystems is of fundamental importance for conservation, man-agement and anticipating the effects of environmental changes. Tailoring existing fire spread modelsto particular landscapes is challenging because it demands a substantial data collection effort. Here we develop an objective way to fit simple stochastic fire spread models based on readily evelavailable data fromdocumented fire events (i.e. approximate ignition point, preexisting vegetation, final perimeter, topogra-phy, and average wind direction). We use a simulation-based approach founded on Approximate BayesianComputation, which allows for a thorough exploration of parameter space as well as the quantification ofuncertainty around best estimates. As illustration, we use data from nine fire events that occurred duringdry years in northern Patagonia, Argentina. We found that fire spreads readily in shrublands, while foreststend to act as firebreaks. Topography has a strong effect not only because fire moves easily upslope butalso because it modulates wind direction. Finally, aspect affects fire spread mainly in forests, probablydue to its effects on fuel moisture. Simulating fire spread sampling parameters from the approximatedjoint posterior distribution resulted in individual fires roughly similar to the ones used for model fitting.Furthermore, the fitted model was able to produce simulated fire-size distributions in good agreementwith the historical record for dry years in Nahuel Huapi National Park, Patagonia. The approach presentedhere can be used in places where standard fuel models have not yet been developed.© 2015 Elsevier B.V. All