poplar question

Hello
I have been on this list for a while, but never had much to say before I have this little poplar that was was growing near the edge of our property, last year while mowing the lawn my son hit the main part of the tree chopping it off. It was in an awkward spot. The small part survived, so I thought I would try to make a bonsai out of it before it got mowed down again.
Would you mind to have a look at my pics? I'm not sure what to do with it now. I know that I won't be able to do much till it takes in the pot, is it worth while? It's in the pot pretty much the it was in the ground.