Understanding the historic fire regime is essential before restoring fire to an ecosystem. Historical ecology provides a means to use both quantitative and qualitative data from different disciplines to address questions about how the traditional ecological management (TEM) practices of indigenous peoples influenced prairie and savanna ecosystems in the past. In this article, we evaluated paleoecological, archaeological, ethnographic, and ethnobotanical information about the Upper Chehalis River basin prairies of southwestern Washington to better understand the extent to which TEM influenced prairie distribution, composition, and availability of wild plant food resources. We also surveyed areas that had been burned at differing frequencies to test whether frequent fires increase camas (Camassia quamash) productivity. Preliminary results support the hypothesis that camas productivity increases with fire-return intervals of one to two years.