trees is a research project (preliminary study) conducted by the Institute for Computer Music and Sound Technology (ICST), Marcus Maeder, in collaboration with the  Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Roman Zweifel.

ICST members of staff involved: Marcus Maeder, Jan Schacher, Sébastien Schiesser, Phlippe Kocher

Project partner: Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Dr. Roman Zweifel

Partner project: SysSon, Institute of Electronic Music and Acoustics (IEM) of the University of Music and Performing Arts of Graz

Visit our project site.

Plant physiologists have known that plants emit sounds for several decades now. Most of these sounds are of transpiratory/hydraulic origin and are therefore related to the circulation of water within the plant as part of the transpiration process. The frequency of the acoustic emissions is in the ultrasonic range, i.e. well above the audible range. By analyzing these acoustic emissions, we can find out more about plant physiology and the ecophysiological processes in plants: If the sap flow is interrupted inside a plant’s vessels (a phenomenon known as „cavitation“), for example in a severe drought, the plant emits ultrasonic pulses that are imperceptible to the human ear – in other words, they begin to “whisper” in the high-frequency range. This phenomenon shows how atmospheric conditions, diurnal rhythm patterns, light conditions and water reserves manifest themselves acoustically, as it were, in trees.Roman Zweifel from the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) has been studying plant ecophysiology for several years now, focussing on the relationship between plants and diurnal rhythms and climatic processes. Marcus Maeder from ICST conducts artistic research projects, during which he has developed sonification methods for the acoustic representation of a range of multidimensional data. The trees research project, conducted jointly by ICST and WSL, records, analyzes and represents ecophysiological and climatic processes in the form of sound and seeks to create an acoustic and aesthetic experience of these processes. As part of this preliminary project, acoustic emission sensor technology and analytical technology are being optimized in order to understand not only the quantity and temporal aspects of acoustic events in plants but also the quality or acoustic signature of such events. The recordings and measurements taken seek to identify a typology of the sounds emitted by trees, which then undergoes a detailed quality and temporal analysis as part of the ongoing research project. This analysis should help us determine the “what”, “when” and “where” of acoustic processes in plants as well as identify the connections between the sounds and climatic processes and diurnal rhythms. Long-term measurements should enable us to determine whether climate change phenomena are manifested acoustically, too, in trees. As part of this research project, the initial attempts at sonification of climate and ecophysiological data collected by WSL in the test location of Salgesch (VS) during a single growing season are being translated into a 3D-surround-sound installation. Our aim here is to render normally imperceptible ecophysiological processes in trees audible in order to show just how closely connected these processes are to our climate and how important they are in preserving the biosphere.

WSL partner site