The cut trunk sections are lying at 90deg to where the complete trees/trunks would have been lying, so there has had to be some form of machine to move those given their size.That pix is after it flipped up.
I could see where the smaller one might have been "on top" of the larger one.
"height of the cut off the stump" was a horizontal distance when cutting eh ?
The height of the stump is likely due to they'll have just kept cutting sections until it stood up. The main aim would be to make the root ball safe, not to maximise the amount of cut timber.