From the end of Reconstruction to the beginning of World War II, no other ecological change affected as great a part of the southern landscape as the loss of the longleaf pine from the southeastern coastal plain. This dissertation examines the causes and consequences of the species’ disappearance. In the span of just decades, lumber operations and naval stores producers descended upon longleaf pine woodlands with a voracious appetite that greatly contributed to the demise of the pine. However, as this dissertation argues, exploitation by the hands of the timber and turpentine industries was not the only agent that transformed the ecoregion. The development of American conservation and forestry, ironically, played a significant role in this process and contributed to the rise of a new southern forest, now stocked with another pine – the loblolly. By looking at the biologists, chemists, and foresters who studied the longleaf for the United States Department of Agriculture and various state agencies from the late nineteenth to the early twentieth century, this dissertation traces how forest sciences in the Gilded Age and Progressive Era shaped the modern ecology of the South. These sciences, too, were entangled in the social and political realities of Jim Crow. Researchers had to ensure that their measures conformed to a segregated society if conservation was to take root in southern woodlands. The conservation practices that federal and state agents put into place as forestry developed into an important and profitable science had profound impacts on not only the land but also those at the bottom of a racial caste system.