In Science the tree is considered by Botany. The tree is one of the richest images in culture. The tree as tree of life has obvious Freudian symbolism. In India the three trees become the tree of knowledge, the tree of wisdom and the tree of life
and identified with specific species.
Trees Tree of Knowledge Tree of Wisdom Tree of Life
Melia Azederach Mango Banjan Mulberry Ficus Bengalensis
At an abstract level the three trees are associated with the three gunas, At the levels of energies, the three trees become linked with the three nadis of the human body which effectively serve as three pillars or three columns.
Gunas Sattva Tamas Rajas
Nadis Ida Shushumna Pingala
Pillar Mercy Benignity
Banjan Mango Banjan
The myth is as follows: During the time of conjugal meeting of Lord Śiva and Parvati, gods in the heaven learned that the son, who would born out of this meeting, would be a mighty one and would be invincible. He would conquer Triloka: pruthibe (the earth), swarga (the heavens), and patala (the lower realms); he would make all other gods his subordinates. Out of this anxiety the gods wanted to interrupt the union of Śiva and Parvati. So they prayed to BrahmĀ and Vishnu to do the needful. Both BrahmĀ and Vishnu went to the place of Śiva and Parvati and uttered the sacred mantra Om. As a result Śiva became conscious and out of shame he ran away. The whole incident not only upset Parvati; it also raised her anger. She cursed BrahmĀ, Vishnu and Śiva to be immovable. Immediately the three of them were transformed into the trees kimsuka, peepal and banyan respectively. http://www.murugan.org/research/pattanaik.htm