Were I to be a tree, I would be the mighty baobab tree! Roots are branches, up is down! I would dance about and stir up wonder about whether things are what they seem. Are those roots in the air? This is very un-treelike!
I would use this power to remind mankind that the world is full of puzzling things, and not to be afraid of contradictions.
The baobab is the Tree of Insight, and mankind is nourished by his insights.