I don't know how large medium sized is but if a wild tree is over 1" in diameter it's going to be pretty hard to successfully transplant. I've transplanted 4 & 5" shallow rooted trees like dogwoods successfully. The secret is never let the soil get dry for a year after transplanting.
If you have the time & patients you can spade around the tree trimming the roots & then let it go through 1 growing season before transplanting.
