A surround-sound installation from the research project trees of the Institute for Computer Music and Sound Technology of the Zurich University of the Arts and the Swiss Federal Institute for Forest, Snow and Landscape Research WSL.
Artistic realization: Marcus Maeder (ICST)
Collection and processing of measurements: Roman Zweifel (WSL)
The link between trees and various climatic processes is usually not immediately apparent. Trees and plants do not live merely on moisture from rain, sunlight (which drives gas exchange) and nutrients from the soil: they absorb carbon dioxide from the air and produce the oxygen that we breathe, maintaining our climate and biosphere. Hence the importance of conducting scientific research and measurements to explore the complex relationship between tree physiology and our climate and of producing an acoustic and artistic representation of the ecophysiological processes in trees. Rendering audible the way in which water transport and trunk diameter, for example, are influenced by sunlight, humidity and wind allows us to identify and understand better than ever before plants’ responses to climatic processes.
In their research project Trees: Rendering Ecophysiological Processes Audible, submitted to the Swiss National Science Foundation, Marcus Maeder of the Institute for Computer Music and Sound Technology (ICST) of the Zurich University of the Arts and Roman Zweifel of the Swiss Federal Institute for Forest, Snow and Landscape Research WSL are working on the acoustic recording, analysis and representation of ecophysiological and climatic processes and studying the acoustic and aesthetic requirements for making them perceptible. Measurements of acoustic emissions in plants must be analysed and understood in relation to other measurement data such as that relating to the microclimate, sap flow, changes in trunk radius and water potential in the plants’ organs – all measurement data that is not auditory per se. Therefore, in our research project trees, we deal with the sonification of ecophysiological data as well as analysing the actual acoustic emissions. How can processes that are beyond our normal perception be made directly perceptible, creating new experiences and opening a new window on the world for scientists, artists and the general public? To what extent is our sense of hearing of use? For scientists, it is about identifying links, patterns and deviations, whereas for the general public it is about gaining a deeper insight into the workings of nature.
The sound installation Downy Oak exhibited at swissnex in San Francisco is at once a research tool and a work of art. The installation is a prototype of the three-dimensional audio matrix to be developed and used for data sonification experiments as part of the trees research project. The measurements and recordings of sounds in plants are to be analysed and brought together to create a overall acoustic experience. In our sonification experiments, we aim to combine real recorded sounds of natural phenomena such as wind and rain and the virtual sounds of non-acoustic phenomena such as humidity and trunk radius to explore ways to increase the level of immersion of an acoustic observation and representation system. The system in question (the Downy Oak installation) consists of a grid of self-built omnidirectional speakers. Visitors can walk around the installation freely and explore it. At the centre of the matrix is an acoustic representation of a Downy Oak (Quercus pubescens), i.e. the sonification of data obtained by Roman Zweifel of WSL from sensors on and around a tree in the Swiss Alps between 2004 and 2008. The sounds represent the tree’s physiological responses to climatic processes, day-night cycles etc. The local climate can be heard around the Downy Oak in the surround-sound field: wind, rain, humidity and sunshine. But what do sunlight and humidity sound like exactly? For our first prototype, we have created a catalogue of recorded and synthetic sounds; our experiment at swissnex San Francisco consists in determining from visitors whether the sounds that we have created provide an adequate acoustic representation of the phenomena at hand and whether the acoustic representations are identifiable and distinguishable from one another. To this end, we have set up a blog on a computer at the exhibition for visitors to share their experiences of and thoughts on the installation while they are still fresh in their minds.