Hi Frank:
Many individuals encounter poor success when trying to dig up seedlings for transplanting to different locations -- honestly, you're better off buying barefoot seedlings at $0.50/each in my personal opinion.
However, the goal to successful transplanting is to dig up as much of the root ball as possible while minimizing damage to the tap root and lateral roots. This small task can be more difficult than you think since some tree species have very robust root systems.