Forest fires scorch trees, shrubs, and the soil surface, but what are their impacts on deeper soils and the microbes that live there? Tree roots can grow as deep as 5 meters (16 ft) or more, interacting with diverse bacteria and fungi in soils, and potentially controlling how much, and how quickly, carbon moves from the atmosphere to the soil and back. When trees die suddenly in a high-intensity fire, their roots are left behind to rot. This changes which microbes are present, how they interact, and how carbon moves through the soil. In this study, researchers will sample the entire rooting depth of both living and fire-killed ponderosa pine trees to understand how microbial communities change when a tree dies—and how those changes affect how much carbon the soil holds, and for how long. Using these data, the team will build models to predict how fire alters soil processes at the scale of forested landscapes and ecosystems, and how changes to the frequency and size of forest fires could affect these soils in the future. This project will support the next generation of scientists, providing opportunities for a graduate student and a postdoctoral researcher to lead field, laboratory, and modeling work. Undergraduate students will receive hands-on training in processing soil samples and analyzing data through research internships. The PI will also design a first-year seminar focused on microbial ecology, creating a Course-based Undergraduate Research Experience to help students