Q.Robinia Tree
How can I move a young Robinia tree and when is the best time to move?

Certified GKH Gardening Expert
Fall is a good time for transplanting. If you cannot do so now, then spring would be ideal. Get as much of the roots as possible and replant in a suitable location. In order to reduce the amount of stress on the plant from moving it, you may want to consider cutting it back. This article will also help:
https://www.gardeningknowhow.com/plant-problems/environmental/learn-how-to-avoid-and-repair-transplant-shock-in-plants.htm