This study is part of a two-part study to investigate the potential for using national-scale climatic information to make spatially explicit predictions of fire risk. Fire risk is generally defined as the probability of initial ignition of fires. In practice, this combines both the ignition sources, and the fuel and weather conditions that allow a potential ignition to catch and spread. Fire risk was modelled as a function of environmental and cultural factors using a modern spatial analysis
technique. Spatial predictions of fire risk were made for the Wellington Region and the North Island, using generalized regression analysis and spatial prediction (GRASP).
A dataset of 1390 fires reported to the NRFA in the Wellington region over the decade 1989–1999 was used as the observed fires. For the purposes of modelling from this dataset, fire risk was defined as the probability of one or more fires per hectare per decade. A number of spatial predictor layers were developed for this project, including five climatic, three landform, two cultural variables and one landcover variable. The resulting statistical models of fire risk were imported into a geographic information system (GIS) and used to make predictions of fire risk.
This project demonstrates the feasibility and power of GRASP methodology to make spatially explicit predictions of fire risk. Using an incomplete data set confined to the Wellington Region, this approach yielded predictions within this region that accord well with the overall occurrence of fires. The results of this approach could be improved considerably by more comprehensive information on fire locations and continued improvement in spatial information that may act as spatial predictors.