Trees have voices, but they are mostly inaudible. For several decades scientists have been studying the acoustic emissions of plants in order to gain insights into plant physiology. A paper published by Milburn and Johnson in 1966 on the conduction of sap describes a method that the researchers developed to measure a phenomenon termed “cavitation”, a kind of embolism occurring in a plant’s vascular system when it becomes dehydrated. The researchers attached severed leafs of a plant to the needle of a record player and observed how the leafs, while gradually drying up and desiccating, would produce acoustic clicks that the record player was able to amplify. While these scientists employed an instrument designed for the reproduction of music to study the acoustic emissions of plants, more recently Marcus Maeder has approached this field from the opposite end, using scientific measurement tools to create works of sound art. Maeder is leading the research project “Trees: Rendering Ecophysiological Processes Audible” at the Institute for Computer Music and Sound Technology in Zurich. Having gathered audio recordings and environmental data from several forest areas and species of trees, the material obtained is presented within a series of spatial sound installations that employ a matrix of custom-built omnidirectional loudspeakers. The loudspeakers are suspended in the shape of a cube formed by 9 columns of 4 speakers each. Using virtual imaging techniques field recordings of climate conditions are projected outside of the boundaries of the installation, while recordings of the acoustic emissions of trees are reproduced within the installation on individual speaker columns. Physiological data gathered from the forest environment and from the trees is used to articulate the playback parameters of the audio recordings, so that parameters such as the recorded temperature affect the loudness of the installation. Visitors are presented with an auditory experience in which the combination of both recognizable and previously unheard sounds create a sonic representation of natural processes, attempting to convey the complexity of specific ecological systems through correlations between processed environmental data and recordings of acoustic phenomena. Matteo Marangoni

Marcus Maeder live at the Lodge/Zurich – excerpt