A GIS-supported model for the simulation of the spatial structure of wildland fire, Cass Basin, New Zealand.
Abstract
The behaviour of wildland fire in spatially heterogeneous landscapes was simulated using a model (PYROCART) that integrates the Rothermel fire spread model and a geographic information system (GIS). The principal aims of the research were to test the applicability of fire behaviour models to New Zealand ecosystems, and to assess the applicability of GIS to fire spread prediction. The model was validated using an uncontrolled fire that occurred in the Cass Basin, South Island, New Zealand in May 1995. This fire burnt 580 ha across a complex vegetation mosaic comprising shrubland, stands of Nothofagus solandri var. cliffortioides, bog and tussockland. The overall predictive accuracy of the model was estimated to be 80%. Prediction accuracies within different fuel types and slope angles are also presented. Fuel type and slope appeared to be the dominant influences on fire spread. No trends in prediction accuracy by wind speed or direction were apparent. The predicted burn area and the real burn area had a similar overall shape. It was observed, however, that at high wind speeds the model tended to over-predict rates of fire spread in some directions. It is suggested that the PYROCART model showed potential as a land management tool, especially for the testing of hypotheses concerning land management strategies. It is concluded, however, that due to the complex input data and parameterization techniques it requires, it may be less suitable for in situ fire management.