Trees in Containers or Rooftops?

Question concerning Trees in small areas.

From what I recall hearing, trees should be directly planted(ideally from seed) in there destined spot.
Starting trees in containers is supposedly problematic due to the tap root not being able to root deeply.
Does that sound correct?

If so, is there still any clever work around to successfully plant trees in containers or say even, rooftops?
Might sound crazy but, just wondering.