Tanis, Oh, if that is your reason for this, I'd suggest that you try some
root cuttings on their own, all the very small roots you can get, and then
make some root grafts from the top of the tree. Several reasons for doing
this: In case the roots alone fail, you will have an exact copy of the
original tree so you can do "stooling" to get more, and most important
perhaps is so you don't add any viruses the tree doesn't already have. If
the tree is truly a seedling, you will have the chance to propagate it and
study it without complicating the situation with another scion yet.
As for root cuttings, again harking to rose propagation, I think it's
Corn Hill nursery in Canada that is using little tiny root cuttings to
produce own root roses. They lay them on peat moss in styrofoam cups and
put them in a mister. You might want to contact them if you'd like to know
anything about hormones or temperature. Donna