The Sleeping Tree (Pohon Tidur) is a project started by Victoria Pratt and Ben Eaton from the UK-based arts studio Invisible Flock. The project produced an immersive, durational arts installation (first shown in Brighton, UK in 2021) composed from environmental data and 5000+ hours of audio recorded over the course of a month in the forests of North Sumatra, Indonesia. Working with rangers from the Leuser Conservation Forum (FKL) and scientists and data from Landscape Ecology and Primatology (LEAP), Invisible Flock traced some of the few remaining siamang in parts of the forest they were able to access, using LiDAR to scan the siamang's specific 'sleeping trees'. They also developed the Open Field Recorder, an open-source platform for remote long-form bio-acoustic recording. The project publication is available in Bahasa Indonesia (Indonesian) and English.