I had put a piece of root in my cutting propagation  box and left it in for five weeks and it put on 4 1/2 inches of new root growth without even being attached to a plant. Whereas the other pieces of severed roots that were kept in the refrigerator crisper for about 4 months have not even woken up yet. 

 I find it amazing that roots can stay alive for so long and can continue to grow.
 
 Below are 2 pictures of the still growing root and one of the dormant refrigerated roots.

Sam this makes me wonder, with some trees like hardy chicago that can freeze to the ground with 100% top kill can resprout from the living roots. so if this root of yours keeps on growing and thriving then shouldnt it one day sprout from the root a tree. just a thought and a worthey test to try. some would say to graft the root to a scone but i myself would like to see what would happen with just a root that wont stop growing. very intresting. thanx for posting and please keep us updated.

Pretty sure the root alone lacks all of the proper dna to produce a tree