Elm identifications and what to do with collected tree??

[Bonsai2014]

After having troubles wintering some trees in my collection I decided to collect some native species that are used to the harsh winters we have in Wisconsin. I collected a tall elm that was snapped off along the edge of a field. it stands 34" from soil to the break. I plan on letting it rest this year and build some roots and ramify. I am wondering if anyone has any suggestions for this plant.
I will attach 3 pictures of the whole tree, and closeups of the leaves and bark. I am assuming this is a Ulmus Pumila or Siberian Elm. The 4th picture is from a group of seedlings I collected. The leaves are dark green and only half an inch long but I know it is not a Chinese or lace bark elm but the leaves are not as sharp on the edges and do not come to a point.

Any advice is appreciated!

 

[M. Frary]

Good call. It is Siberian elm. I have several. These are very vigorous growers. I've dug stumps with only 2 feeder roots and it took right off. You could chop this lower right now and it would be fine. Up here it would grow a leader 4' to 6'. The one thing you will be warned about is that it will drop a branch for no reason. I think if you tickle the roots every spring that may not happen. Keeps them on their toes so to speak. Even so they are great trees to start on.

 

[Bonsai2014]

Thanks for the advice. It's odd that the two trees have such different leave sizes. I have a few saplings that have already dropped a few small branches out of nowhere. I am contemplating air layering this tree and turning it into two. My goal with the Siberian Elms I have collected it to form a forest planting on a slab. I figure this way it will be a "little" more forgiving with some dieback.

 

[MidMichBonsai]

There does seem to be a bit of reverse taper midway up the trunk. If you do attempt to airlayer, I would do if at that point. Otherwise, I would give it a trunk chop to develop the trunk into something with more taper before worrying about design or placement of the branches.

Good luck!