My dissertation constructs an ecological history of the Sumatran rainforest in the Gayo highlands of Aceh, Indonesia from 1900-1945. How did this remote highlands region, not accessed by Europeans until 1903, become a center of tropical conservation and exploitation by the 1920s? How were the traditional territories of the indigenous groups transformed into a ground zero for the transnational environmental movement? I argue that the Sumatran rainforest, as the conceptual, and in many instances, actual property of the Global North is a remnant of colonialism and neo-ecological imperialism. In 1904, after forty years of war in Aceh, the Dutch colonial government finally assumed administrative control over the region. Their first move was to implement laws that created formal land ownership, accumulating indigenous territories into state possession. Soon afterwards, the Dutch opened the highlands to the world and the space quickly became a cosmopolitan intersection. Chinese, Tamil, and Javanese immigrants arrived to work on plantations, foreign researchers explored the forests to study the biodiversity, and American trappers collaborated with indigenous peoples to search for valuable animals and plants to smuggle to zoos and museums around the globe. In this regard, I contend that the intercultural encounter between local people and foreign researchers and animal and plant collectors was crucial to the development of modern conservation and environmentalism. I will use archival sources collected from four different countries, along with ethnographic data and oral histories I have already gathered from five months of research in Aceh, to historicize the spatial production, exploitation, and conservation of Sumatra's rainforests. Beyond scholars of Indonesia, the global nature of my project speaks to broader audiences from various disciplinary perspectives, including historical geography, agrarian studies, environmental humanities, and transnational studies.