[RHSeeger]

I'm not sure why you say I missed that. I didn't. Can you expand on what you meant by your reply.

To me, your reply actually highlights what I was talking about; because your use of "this phenomenon" is _somewhat_ ambiguous.

1. "this phenomenon" can be the sound of "large pressure splits in tree trunks, caused by sap freezing and expanding" (presumably audible to humans)

2. "this phenomenon" can be the sound of "freezing sap in trees" (presumably not audible to humans)

[solardev]

Seems like they would've recored both in the field, no? If they were recording sap freezing in the field, presumably the mics would pick up on other parts of the tree undergoing stresses and making audible sounds.

For that to have not been the case, either they would've had to freeze sap in the lab, or they would've had to go way out of their way to isolate recordings of just the sap in the field without the rest of the tree (is that even possible with normal recording tech?)