Folk Biological Value and Chestnut Conservation in Turkey. An ethnobotany dedicated to biocultural survival must advance research methods that perceive and support the biological basis of cultural survival in tandem with the cultural basis of biodiversity maintenance. To help address this challenge, we introduce the concept of "folk biological value"-the value of the more-than-human living world to cultural cohesion and survival-as well as a method to investigate and apply it to an ongoing biological conservation endeavor. In Turkey, the sweet chestnut tree population (Castanea sativa Mill.) is threatened by multiple exotic pathogens. In order to engage and study the collective value motivating continued chestnut presence and association, we sampled communities along the legible value structure of the value chain. We conducted 162 group interviews with 12 chestnut value chain groups across Turkey. Our results show how botanical knowledge of the tree transforms significantly in correspondence to the flow of the value chain. Further, we demonstrate that while the Black Sea region and western Turkey represent distinct human geographic zones of chestnut engagement, the most substantial countervailing forces defining nationwide conservation priorities are commercial and local maintenance value. This research furthers understanding of and capacity to engage community value during urgent local transitions from ecological protection to prioritization.