Forest Gardens in High Tunnels?

I love the idea of a forest garden! What are your thoughts on planting small-scale forest gardens within a high tunnel system to mimic a sub-tropical climate? Or to mimic a warmer climate in general if you lived somewhere with a cold climate/shorter growing season such as Alaska? Is it possible to train or prune fruit trees in a small space such as this to keep them small while still growing them directly in the soil?


Thanks,
Cheyanne