Rowans are sometimes found growing out of the stumps of other trees or even out of their boughs, or out of an inaccessible cleft in a rock, so not in the ground at all and are known as flying or journey trees. They are thresholds between the worlds.
This pic is a Rowan growing out of an Oak stump at one of my favourite portals on Exmoor. It stands at the beginning (or end) of a magical path into (or out of) a wild forest. That forest has so much in it. There’s an ancient ring-fort by the river that’s an incredible place to sleep in, we’ve done that several time and the dreams are amazing. It’s by a place where a wild brook churns down from the moors to join the river, and that’s where kelpies play and try to entice you to swim with them. There’s an old bridge across the river, connecting a hillfort at the top of the hill to the ring-fort at the bottom. The bridge has been slowly falling to pieces all my lifetime, Dad first too me there when I was about 5, it was quite reasonable