> Trees are loud, like really loud, but we can't hear it at all since it's all ultrasound.
Just to put loud in perspective: seems like cavitation produces ultrasound in the ~30db range at the highest[1], which is roughly the level of a whisper. I haven't knowingly captured trees in my ultrasound field recording, but it seems fun to try. That should be loud enough to pick up something with an ultrasonic recorder close by, I'd think, which is pretty cool -- I assumed you'd need to do something like David Dunn and embed microphones into the trees.
Just to put loud in perspective: seems like cavitation produces ultrasound in the ~30db range at the highest[1], which is roughly the level of a whisper. I haven't knowingly captured trees in my ultrasound field recording, but it seems fun to try. That should be loud enough to pick up something with an ultrasonic recorder close by, I'd think, which is pretty cool -- I assumed you'd need to do something like David Dunn and embed microphones into the trees.
[1] https://nph.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-...