This paper examines the intersection of environmental history and the history of science, specifically the impact of forestry science and fire management on land use and community dynamics in rural Portuguese mountains. It further traces the evolution of fire management from an ancestral rural practice to a scientific concern and the subsequent integration of vernacular knowledge with scientific methods. In the early twentieth century, fire was a common tool in rural Portugal for land clearance, pasture management, and soil enrichment. Rooted in local knowledge, these practices were increasingly challenged by the rise of scientific forestry, which viewed fire primarily as a threat to be controlled. By the mid-twentieth century, Portuguese forestry policies had undergone a significant shift toward aggressive fire suppression and large-scale afforestation, reflecting a broader trend of prioritizing timber production and forest protection. Notable shifts occurred in the 1970s, marked, among other factors, by the increase in rural fires, a new socioecological vision for the forest and the introduction of prescribed fire techniques influenced by international models. The paper argues that the establishment of scientific fire management practices represents a merging of expert knowledge with local experience. This move represents a shift from exclusionary policies toward a more nuanced understanding of fire's role in landscape management. An examination of these historical developments demonstrates the intricate interrelationship between science, the environment, policy, and local practices, illustrating the way knowledge systems both shape and are shaped by environmental governance.

Keywords: Forestry science; Portugal; commons; fire management; land use.