A GIS-supported model for the simulation of the spatial structure of wildland fire, Cass Basin, New Zealand

1. 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). 2. The principal aims of the research were to test the applicability of overseas fire behaviour models to New Zealand ecosystems, and to assess the applicability of GIS to fire spread prediction. 3. The model was validated using an uncontrolled file 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. 4. 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 burnt area and the real burnt area had a similar overall shape. It was found, however, that at high wind speeds the model tended to over-predict rates of fire spread in some directions. 5. The PYROCART model shows potential as a land management tool, especially for the testing of hypotheses concerning land management strategies, However, due to the complex input data and parameterization techniques it requires, it is less suitable for in situ fire management.