The World Tree is the Single Fig-tree, the Bodhi or Awakening Fig-tree. The sap of the tree rises from the roots to the foliage. The roots correspond to the authentic Braman, to the Principle to the source of manifested and non-manifested, the branches and the foliage to the actual manifestation. From the manifested being standpoint nevertheless, the Principle comes under the world beyond and its manifestation within the world here below. This is the reason why, the tree is perceived inverted from the manifestation standpoint.
Buddhism drew from Hinduism in the beginning. It had to distinguish itself from it and develop its own path in order to overflow Indian borders and be adapted to new regions. Nevertheless, this does not prevent symbols as the World Tree or the Tree of Life from still carrying the stamp of the pre-Buddhist period as testified by the Vedas and especially the Upanishads. Besides, the description of the tree in the Maitrayani Upanishads illuminates this point:
The light of the authentic Brahman is the one of the spiritual Sun proper to the invisible world and beyond the visible sun. It is not only a matter of the light received at the time of Enlightment, Awakening, but also of the light associated with the act of illuminating, awakening. The awakening concerns not only the one that awakens, but equally those on which the Awakened gleams.
Each of these gods represents an aspect of the Principle of the human manifestation as a whole:
“It (the fiery energy) has its place in the dark home that diffuses light… it rises such a branch in the firmament and, stem after stem, spreads all over just as a contemplative vision.” (Maitri Up. VII 11)
Even if it contains some philosophical and religious elements, the Buddhism is neither a religion nor a philosophy. And this is even truer for the Great Vehicle or Great Way ( mahayana ) accessible to the largest number in contrast to the Defective Vehicle or Defective Way ( hinayana ) restricted to monks. The Buddhist doctrine is the fruit of the inner quest of a man that showed the Way of cessation of suffering for ALL beings.
Just as Brahman, the Buddha radiates fiery energy:
Now, an inscription about the Tree of Life in the temple of Angkor Wat, initially Hindu, then Buddhist, stipulates that its roots are Brahmâ, its trunk Shiva and its branches Vishnu.
“The syllable OM… Prana (Vital Breath), Agni (Fire) and Surya (Spiritual Sun) are its fiery forms.” (Maitri Up. VI 5).
The Buddhist World Tree is the Bodhi tree or the Awakening tree which corresponds to the action of getting up.