
Proposed list of TreeMusic Device Measurement Parameters
NOTE: Trees will not be harmed when being sonified. Sap flow changes in the phloem/xylem might correspond to measurable electrical signals influenced by nycthemeral cycles, but no electrodes will be driven into the flesh of the tree to obtain such data.
The central processor in each TreeMusic device is the Teensy4.1.
Sonification would use the voltages measured from several pairs of attached electrodes. Each voltage would serve as the control to its own sine wave oscillator, amplifier or filter using standard FM synthesis. Since various tree species have different measurement ranges, a group of similar sized maples in a stand, for instance, should exhibit a similar ‘voice’ at the same time.
1 • Electrical Potentials: Surface electrodes on the tree’s bark is the simplest, most direct measurement. These voltages vary by species, commonly ranging from 10 to 2000 mV. In storm conditions, voltage potentials can exceed hundreds or even thousands of volts. Electrodes would be placed vertically, higher up and lower down the tree’s trunk or branches. The lower electrode could be driven into the near ground with a copper stake.
2 • Capacitance or Resistance: Measuring capacitance or resistance of the tree tissue alongside voltage could provide additional layers of data. Changes here might indicate hydration levels or ionic flows within the tree. This might be accomplished with metal plates (could be metal fabric) placed on the opposite sides of the trunk or bough with a LCR testing device or circuit.
3. Leverage Circadian Rhythms
Trees exhibit distinct rhythms influenced by light availability. For example, stomatal opening and closing (a diurnal process) impacts the flow of water and ions. This might be tracked and translated it into sound dynamics, where mornings might have one pattern and evenings another.
4. Environmental Inputs as Modulators
• External factors like light intensity, temperature, and humidity affect tree signals. These could be secondary modulators in the sound synthesis circuit. For instance:
• A photoresistor could track sunlight and shift tonal characteristics based on light levels.
• A temperature sensor could adjust pitch or timbre to reflect changes in ambient temperature.
5. Multi-layered Sonification
• Combine real-time voltage data with other real-time factors to generate complex soundscapes. For example:
• Voltage → Pitch: Direct sonification of voltage ranges to pitch.
• Capacitance → Timbre: A timbral shift based on hydration or resistance.
• Environmental Modulation: Humidity or light data to control volume or effects like delay/reverb.
6. Adaptive Synthesis Techniques
• Use probabilistic or generative synthesis techniques to create variability in the soundscape. For instance, my circuit could respond to tree signals within defined rules (voltage thresholds) but add randomness or “behavior” to emulate the natural variability of life.
7. Incorporate Nycthemeral Patterns
• Since I am considering nycthemeral rhythms, I could design the circuit to adapt to day-night cycles. For instance:
• Daytime: Bright, rapid, high-frequency sounds.
• Nighttime: Slower, darker, low-frequency tones.
8. Data Visualization Integration
• Alongside sonification, I could add LED visual feedback to the circuit. A simple RGB LED can shift in color based on the voltage range or time of day, creating a multisensory experience.
9. Experiment with Biofeedback Loops
• I could also create an interactive system where sound generated from the tree impacts its environment. For example:
• Emit sound back to the tree at specific frequencies to see if there’s a measurable response.
• Use light pulses driven by sound to stimulate photosynthesis or affect stomatal behavior.
10. Portability and Connectivity
• The system is to be small and portable, so, perhaps I should:
• Explore Bluetooth or LoRa to transmit real-time tree data to a more robust synthesis engine (e.g., a laptop or Raspberry Pi for richer sound possibilities).
• Include an SD card slot to log data for later analysis.