BG Chap 15 - The aśvattha tree, its leaves and branches
The aśvattha tree is considered the best of trees because it has fruits in the form of dharma, artha, kāma and mokṣa. The word aśvattha can be split up as a+śva+ttha – ‘not tomorrow stay’ or that which will not exist in the future. For the devotees, the world will not exist in the future because they would become liberated and attain the spiritual world. For the non devotees, the tree will not exist because everything they are attached to will cease to exist. But the material existence for the non devotees is eternal. This tree is eternal in the sense of being continuous, because it does not disappear except thru discriminating knowledge.
Just as the leaves of the tree nourish the tree and make it attractive, the statements of the Vedas which propound performance of kāmya-karma make material life attractive and increases the attachment of the soul to the tree (world). Thus the Vedas are considered the leaves of the tree. For example, the Taittirīya Samhitā says one should sacrifice a white horse to Vāyu desiring wealth and power. One who understands this aśvattha tree is a knower of the Vedas because the Vedas also give knowledge how to cut down the tree of saṁsāra.
The branches of the tree extend up and down, nourished by the three modes of material nature. They (material bodies) spread downwards by the jīva’s committing sinful acts and being born in the bodies of men and animals, and they spread upwards by jīva’s performance of pious acts and being born as devas and Gandharvas. By the actions of the modes, like sprinkling of water, the branches (bodies) increase in number. The sense objects such as sound are considered to be shoots of the tree because they are in immediate contact with the senses just as the buds are joined directly to the tips of the branches. The branches (bodies) have tips (senses), which have shoots (sense objects), which are sources of enjoyment. Just as the new leaves give color and beauty to the tree, the sense objects give enjoyment to the senses and body.