I was very surprised to find that a lot of stumps have a single post under them supporting the bulk of the head of the stump that you see above the water. I guess over the years, the top soil erodes away. That exposes the branches of roots you see from the big elaborate river stumps on reservoirs like Kentucky Lake. But as time passes on, the tips of the roots rot back towards the stump. The thickest root I’m guessing is usually at the core of the stump, so it’s the last to rot.
My house has a round dining room table with a single center column. My dog constantly hides under there when a stranger comes in the house. Most of the time you can’t even see the dog under there and she can’t see you.
I realized the same thing was going on fishing these stumps. I would throw over a stump six times with a topwater and all the sudden on the seventh cast, a big bass would kill my bait. Where was he that whole time? My guess is on those table top stumps, they suspend right under them as that would be the deepest darkest shade. So it probably takes a handful of casts to coax it out where it can see bait coming from a distance.