Hi Bill,
These are just roots left in the ground after digging around the root ball of the plant for potting and bringing in doors. As you know, it's impossible to get every root. Once the tree was dug I pulled up a few of these roots. Some were about half an inch thick, others were the size of a pencil. If you plant these roots in a pot, have them go dormant, bring them in for the winter, will they send up shoots next year once brought outside? Has any one ever tried this?
Ps. I owe you some fertilizer Bill. Been delayed in getting to central PA but hopefully soon!