TreeNoc
Acoustic Internal Decay Detection for Standing Trees
Duration
2025
Researcher
Hanju Seo
Affiliation
- EarthCode Ltd.
Role
- Principal Investigator
- Hardware Designer (acoustic sensing rig)
- Embedded Systems Engineer (actuation & signal processing)
- Field Researcher
A tree can appear healthy from the outside while its interior has already begun to fail. Decay colonies advance through heartwood silently, leaving no surface trace until structural compromise is severe. TreeNoc addresses this gap by developing a non-invasive acoustic sensing system capable of detecting internal decay in standing trees without cutting, drilling, or attaching permanent markers.
The system operates through a controlled emit–propagate–receive–analyse sequence. A solenoid actuator delivers a precisely timed mechanical strike to the trunk surface, generating a low-frequency acoustic pulse that travels through the wood. Three piezoelectric receivers positioned at measured intervals around the circumference capture the transmitted signal. Sound moves differently through healthy wood and through decayed or hollow tissue: decay slows transmission and scatters the wavefront. By comparing arrival times and signal characteristics across the three receivers, the system builds a spatial picture of what the bark conceals.
The hardware was designed for field deployment: compact, battery-powered, and operable without specialist training. EarthCode developed TreeNoc as part of a broader research programme into non-invasive sensing infrastructure for living trees, extending the same core commitment that runs through Bark-Code: that forest data should be collectible without harming the forests it describes.
Solenoid actuator setup, piezoelectric receiver placement, and acoustic signal analysis during field testing.