Dug up, cleaned, and potted a huge multi-trunk maple I found late last year. Lots of fine roots, but the groundsoil was a wet, sandy mess. I tried my hardest to get as much of the old material out of there but had quite a bit left. It's potted with a mix I use for newly collected trees which is 2:1:1 pumice, bark fines, dried sphagnum, and an extra 0.5 of manure compost. I also watered it in with Cannazym, a product for hydroponic cannabis growing that breaks down dead root material and encourages new root growth. I haven't decided on the final length of the thickest part of each trunk, I figured I'd wait a season to see how it grows in and then make cuts at next budbreak.
In a couple weeks I'll collect one or two hornbeams, and a thick winged elm after that.