Non-parametric comparative analysis of the spatiotemporal pattern of human-caused and natural wildfires in Galicia

Abstract

Background. Wildfire is a major environmental threat worldwide and climate change is expected to increase its severity. Galicia has suffered high wildfire incidence during the last decades, most wildfires being from arson, in contrast with the low rate of natural wildfires. Aim. This work aims to characterise the spatiotemporal dynamics of human-caused and natural fires in Galicia. Methods. We apply first- and second-order non-parametric inference to spatiotemporal wildfire point patterns. Key results. The distribution of natural wildfires remained stable over years, with high incidence in summer and in the eastern area of Galicia. Arson wildfires had aggregated patterns, with strong interaction between outbreaks and fires, and their distribution varied both over and within years, with high incidence shifting between the southern and western areas, and high hazard in early spring and late summer. Negligence wildfire patterns showed short-distance aggregation, but large-distance aggregation between outbreaks and fires; their spatial distribution also varied between and within years. Conclusions. Different models and covariates are required to predict the hazard from each wildfire type. Natural fires are linked to meteorological and environmental factors, whereas socioeconomic covariates are crucial in human-caused wildfires. Implications. These results are the basis for the future development of predictive spatiotemporal point process models for human-caused wildfires.