In this article, I argue that conservation science in its role of advocate for the natural world could profitably draw from site-specific histories that integrate human and natural histories. Both fields analyze the dynamic interaction of structure and process. In East Africa's Eastern Arc Mountains, where forests contain high levels of species endemism and biological diversity, the prevailing historical paradigm from conservation science represents today's forests as surviving fragments of much larger forests. This view builds upon a century-long tradition of scientific scholarship that has developed theories for the evolution of Eastern Arc forests that encompass geological time scales. However, the relatively brief, millennialscale land-use history of the mountains, insofar as it is currently understood, suggests that human manipulation of forest biota involved periods of deforestation and regeneration, as well as the introduction of exotic plants.