Is it possible to graft shagbark, shelbark, pecan and hybrid from these on other rootstocks like oak or another type?
Thank you for info
Generally no, it is not possible. Oak is in the cup bearing family with beech and chestnut. Hickory are in Juglandales which is closer related to walnut. Pecan rootstocks are commonly used for other hickory family members because they grow faster than most of the other hickories. Best results are from matching ploidy level with 32 chromosome hickory species fairly easy to inter-graft. It is more difficult but sometimes feasible to graft 64 chromosome species such as mockernut or pignut. I’ve tried Pecan scions on Mockernut rootstocks and have not been able to get one to take.
I updated the hickory wikis with ploidy levels a few years ago. You should be able to figure out what is most compatible with a bit of reading. One note, hickories are divided into two groups, the true hickories (Carya) and the pecan like hickories (Apocarya). When making crosses between species, it is usually easiest with closely related parents and with parents of the same ploidy level. Hickory - Wikipedia
One note, Carya Ovalis and Carya Glabra are now generally recognized as ecotypes of the same species, Carya Glabra. I’ve seen trees identified as one or the other and really can’t tell the difference even after exhaustively comparing for supposed differences.