I've got a real mystery here. About 10 years ago I had an extension added to
my asphalt driveway. The last couple of years I noticed that it was starting
to heaving at the seam between the new and old portions. Since there's a
mature ponderosa pine about 10 feet away I though OK the pine sent a root
that's picking up water leaking into the seam.

So I chopped up the asphalt and dug down. What I found blew me away. It was
a large twisted network of lumpy roots, up to 4 inches in diameter, twisting
back and forth on themselves, amounting to maybe 30 pounds of wood in total.
But the really weird part is that there was no connection to the pine or any
other plant outside the driveway. There was a number of smaller branches
going off into the soil in various directions but none of them connect to
anything. They all just die out in the soil.

So here I have a rapidly growing chunk of root apparently not connected to a
tree. Is that possible?