A Geodatabase of Historical Indigenous Fire Practices in the Pacific Northwest

Indigenous communities across the Pacific Northwest (PNW) of North America historically used fire for subsistence and cultural practices. Burning occurred across multiple seasons as fuels and weather permitted, including late winter and early spring in some regions. Regular, mixed-severity burns were applied to enhance resources, support hunting and game management, and maintain ecosystems, with these practices having the ancillary effects of reducing fuel accumulation, improving habitat, and mitigating wildfires. Fire suppression in the 20th century, including the prohibition of Indigenous burning and the suppression of lightning-caused fires, resulted in widespread fire exclusion and decreased fire frequency. However, with increasing fuel accumulation, invasive species, and climate warming, fire probability has increased in many systems, contributing to higher fire frequency, fire severity, and burned area. Interest is growing in restoring Indigenous burning for rebuilding resilience in fire-adapted ecosystems, but implementation remains limited by regulations, land ownership, and in some areas, loss of knowledge. Here, we document historical Indigenous fire practices in the PNW and synthesize these observations into a geodatabase. Through a literature review, we collected data on historical Indigenous fire practices including cultural–linguistic group, location, seasonality, frequency, purpose, severity, post-burn vegetation response, environment, burned area, fuel type, and uncertainty. The geodatabase contains 73 observations linked to 36 ecosystem polygons from California to Alberta, showing that Indigenous burning historically occurred during multiple seasons but mostly in the summer and fall, and was primarily for resource enhancement, hunting and game management, and ecosystem maintenance purposes. Our research provides insight into historical anthropogenic fire, supporting the integration of traditional fire knowledge into wildland fire management. Key Points The use of frequent, mixed-severity fire was widespread across the Pacific Northwest and mostly occurred in late summer and early fall. Fire was primarily used for food crop, medicinal, and basketry resource enhancement, hunting and game management, and ecosystem maintenance. This geodatabase links historical fire practices to Indigenous territories to inform future fire stewardship.