This article explores the imaginary of the sustainability of the native forest, through an ethnographic approach to the discourses of inhabitants of the valley of the San Pedro River, Province of Valdivia (Chile). It addresses the complexity that represents, from a scientific-social perspective, the conservation of fragmented ecosystems immersed in diverse and unequal cultural and productive matrices, and that have been the object of the implementation of a public-private conservation strategy called Valley Conservation Landscape San Pedro River. We investigated the sociocultural processes and the meanings and uses attributed locally to the forest and its sustainability. Based on the findings, we invite to reflect on the notion of heritage weft as a concept that, in contexts similar to that of this study, can account for a series of physical and symbolic, material and immaterial aspects, which coexist and whose interrelation makes sense and value to people. In this way, we propose a look to address the management of the conservation of the austral forest, taking into account local history and the various biological, environmental, economic and social processes that have shaped the territories.