The conservation-management of living beings is not only an issue in medicine. Based on a collaboration between a sociologist and a geneticist, this paper aims to document the banking practices in the sector of forest genetic resources, which raises specific questions. Drawing on a fieldwork investigation we further explore the various possibilities that biobanking in forestry conceal in terms of diversity of banked entities and banking practices. We argue that there is a consistent heterogeneity of entities and practices, which reflects the distribution of the agency conferred to the involved entities. This heterogeneity is related to the awareness of uncertainties, which change the relative importance of the different modes of agency in biobanking. Beyond seldom recognition of the diversity of modes of agency, we conclude by claiming for the need of a consistent agency policy.