That's an interesting effect. Similar but not identical to fulgurites.
Quote:
Fulgurite - Wikipedia
https://en.wikipedia.org/wiki/Fulgurite
Fulgurites (from the Latin fulgur, meaning "lightning"), commonly known as "fossilized lightning", are natural tubes, clumps, or masses of sintered, vitrified, and/or fused soil, sand, rock, organic debris and other sediments that sometimes form when lightning discharges into ground.
|
The underground pipe theory is interesting but it seems unlikely it would lead directly to/from the tree.
This PDF
https://arxiv.org/pdf/2108.13788.pdf is troublesome to quote, but page 3 has diagrams of interest
Quote:
Figure 1. Locations of 38 sites in the southern hemisphere along the boundary of the Antarctic
lithosphere plate (yellow circles with corresponding numbers) and magnetically conjugated sites in the
northern hemisphere (red circles with corresponding numbers) were calculated for geomagnetic
conditions of 2000.
Figure 2. Geomagnetic field lines connecting magnetically conjugated sites shown in Fig 1.
|
What I find interesting is that the Northern line runs down the Rocky Mountain range and then flips sideways across the bottom of the Caribbean, and then resumes at Newfoundland. Weird.