Plant physiologists have known that plants emit sounds for several decades now. Many of these sounds are of transpiratory/hydraulic origin and are therefore related to the circulation of water and air within the plant as part of the transpiration process. The frequencies of these acoustic emissions lie mostly in the ultrasonic range. Some of these emissions (so-called cavitation pulses) are indications of embolism in the water transport system, which occurs when a plant is subjected to drought stress and desiccation. Gathering ecophysiological data (i.e. conducting additionally measurements of the local climatic and environmental conditions and of the physiological processes within a plant in response to these) has become an important method in research on climate change and vegetation dynamics. It helps to determine physiological thresholds of plants in terms of increasing temperature and consequently drought stress.

The sonification system "trees: Pinus sylvestris" is based on a combination of different data sonification techniques, i.e. playback of original, transposed acoustic emission recordings and parameter mapping sonification, whereby the sound parameters of a sample player (amplitude, pitch and filters) are controlled by the data flow. The different sonification modules are implemented in a software which replays the ecophysiological data of a Scots pine (Pinus sylvestris) in the Swiss Alps throughout a month in 2015.

"trees: Rendering ecophysiological process audible" is a research project conducted by the Institute for Computer Music and Sound Technology ICST of the Zurich University of the Arts ZHdK, in collaboration with the Swiss Federal Institute for Forest, Snow and Landscape Research WSL. trees is funded by the Swiss National Science Foundation (SNSF) and the Zurich University of the Arts ZHdK.