The World Tree is always a three-tiered vertical structure. Its roots reach into the underworld β the realm of the dead, of unconscious forces, of the deep past, of what has been buried or forgotten. Its trunk stands in the middle world β the realm of human experience, of ordinary life, of the visible and manageable. Its crown reaches into the upper world β the realm of the divine, of spirit, of vision, of what transcends ordinary experience.
The tree is not merely a map of the cosmos β it is the vertical axis around which the cosmos is organised. Without the tree, there is no centre; without the centre, there is no coherent world. The World Tree is what makes a habitable cosmos possible β it establishes the vertical dimension (up-down, above-below, sacred-profane) that gives orientation to everything else.
The tree is also a living connection between the three worlds β unlike a pillar or a mountain (other axis mundi symbols), the tree moves, grows, has sap flowing through it, bears fruit, sheds leaves and returns. It is not a static axis but a living system of exchange: what falls from the crown becomes humus for the roots; what the roots draw up feeds the crown. The three worlds are not merely connected by the tree β they are in continuous exchange through it.