The characteristics of a suitable tree includes: Strength to support a load, a large enough diameter to bore a pocket to accept the boom, and lastly, a good location. After all, you can't relocate it!
In this case, the living ash tree ad been struck by lightning, yet still strong. The boom was sourced from a pine tree since the are a bit lighter and therefore easier to handle. Always peel the bark on the boom to keep from beetle infestation and to prevent rotting.