The tree you see posted is what I saw above the ground when I collected it.  With shovel in hand, ...or nearby, I cleared the leaves around the base so I'd see what I had to work with.  To my dismay I saw it had a 10-12" straight section of trunk that followed the ground.  I nearly passed on it, then remembered I could probably airlayer the top off.

The initial attempt at airlayering this tree failed, but after a quick check showed there were no roots forming, a colony of ants, and that I'd used the wrong soil, I remedied each situation and started again.  6-7 weeks later, the tree had roots coming out the bottom of the airlayer pot.  I slipped it off and (thought I) saw plenty of roots.  After I separated the tree I saw that there were fewer roots than I'd thought.  (I'll be checking/removing airlayers before dusk from now on.)

Seeing there were fewer roots than expected, I found some 2-by and propped it up.  (This 2-by was actually propping the parent tree up in the pot but with the airlayer removed, the parent could support itself.)

I was nervous about this one but its had 3 flushes of strong growth since separation (about every 3 weeks or so).  I think it will make it now, so I'm going to start planning its future.

The first picture is from the day I collected it.  Excuse the sweetgum.  The elm is the cascade (180 degrees from how I'd found it, but the only way I could secure it in the pot).
2nd and 3rd pictures are after separation.

The woods behind my house are full of these, though none with any sizeable trunk (other than the huge ones).  From where did you collect this one?  Looks like it's doing well.  What was the "wrong soil" used, and what did you switch to?