Amending the post on August 15 to add this information about lightning from our son Glenn.
Less than 10% of lighting delivers a positive charge to the ground (earth). It usually occurs around the perimeter of the storm miles from where one would be experiencing frequent lightning. It originates from the anvil at much higher altitudes depending on the geometry of the storm.
Positive lightning is usually a single stroke and does not branch. It also delivers ~10 times more energy than the common negative lightning........as high as 1 billion volts and up to 300,000 amps. Not sure who was holding the meter, but anyway.
Trees and most everything else struck by positive lightning do not survive. Trees will explode as per your photographic evidence. The physics of the tree coming apart is simply the water content flashing to superheated steam at slightly less than the speed of light. The poor tree expands way too fast and you saw how far.
Lightning destroyed a tree on our property on Thursday, an ancient oak with Spanish moss hanging from the branches.
This tree, or one like it.
This is the view I got when I drove into the pasture.
Long strips of bark were ripped off and thrown several yards away from the tree.
I drove around what was left, taking pics as I went.
Slabs of wood were thrown away from the tree.
Spanish Moss blowing in the wind
Bark was striped away, limbs were blown off and the trunk of the tree splintered. Awesome demonstration of the power of lightning. We are blessed that all that was affected was a lone tree.