Intro -- Table des matieres -- Into the woods -- Towards an interdisciplinary approach on ancient forests -- Part 1: Perception and management of ancient forests as a natural and cultural heritage -- Part 2: Investigating forest ancientness: advocating for interdisciplinarity -- Part 3: "At the edge of the forest": other ways to think about ancient and old-growth forests -- Conclusions - Reflections on interdisciplinarity in the social and natural sciences from the perspective of disciplinary frontiers in the face of a complex reality -- List of authors.