If you're looking for a big tree, you're going to be looking for a looong time. It's figurative, not literal. It's like a food pyramid, they don't expect you to make a pyramid out of your food, nor will you ever find one in a grocery store. It's meant to display the levels of existence and authority, with the Source/Creator at the top.
Get to know your spirit guide, and when you can AP and you're ready, I'm sure they will help you to travel there.