In the opening of Chapter 15, the speaker of the Gita describes the material world as an eternal Peepal tree (Ashwattha) that is uniquely "upside-down." This verse is the key to understanding the hierarchy of the 21 universes and the path to the Supreme God.
श्रीभगवानुवाच ऊर्ध्वमूलमधःशाखमश्वत्थं प्राहुरव्ययम् | छन्दांसि यस्य पर्णानि यस्तं वेद स वेदवित् || 1 ||
Transliteration: urdhva-mulam adhaḥ-sakham asvatthaṁ prahur avyayam chandasi yasya parṇani yas tam veda sa veda-vit
English Translation: "They speak of an imperishable Ashwattha tree with its roots above and branches below. Its leaves are the Vedic hymns; he who knows this tree is the knower of the Vedas."
With the roots above in the form of Purna Parmatma Aadi Purush Parmeshwar and the branches below in the form of the three gunas i.e. Rajgun-Brahma, Satgun-Vishnu and Tamgun-Shiv, it is an imperishable, extensive Pipal tree, whose divisions, small-small parts, just as there are verses in Vedas, are said to be twigs and leaves. One, who knows that tree of world in detail, is completely knowledgeable i.e. is Tatvdarshi.
Most commentators fail to explain why the tree is inverted. According to the Suksham Veda, this tree represents the structure of the creation under the control of Kaal Brahm.
The "Roots Above" refer to the Param Akshar Purush (Supreme God Kabir). Just as a physical tree is nourished by its roots, the entire creation—including the 21 universes of Kaal and the 7 universes of Akshar Purush—is sustained by the energy of the Supreme Almighty located in the highest realm, Satlok.
The trunk of the tree represents Jyoti Niranjan (Kaal). He is the "Giver of the Gita" and the ruler of the 21 universes. He is the central pillar that connects the lower branches (the material world) to the higher roots.
The branches spreading downwards are the three Gunas:
The leaves are the Vedic hymns (chandāṁsi). Leaves protect and beautify a tree but are not the source of life. Similarly, performing Vedic rituals for worldly gains keeps a person entangled in the "foliage" of the material world without ever understanding the Root.
The tree is upside-down because the source of life (God) is in the higher spiritual dimensions, while the manifestation (the world) is in the lower material dimension. This inversion also signifies that the human soul is "turned away" from its source. We seek happiness in the branches (material objects/minor gods) instead of looking upward to the Roots (the Almighty).
The verse ends with a challenge: "He who knows this tree is the knower of the Vedas."
Ashwattha literally means "that which will not remain until tomorrow." It signifies the temporary and perishable nature of the material world. Although the tree is called "imperishable" (avyayam), it refers to the continuous cycle of birth and death that seems endless.
In Verse 3 and 4 of this same chapter, it is stated that one must cut the attachment to the branches using the "Sword of Detachment" and then seek that Supreme Abode from which no one returns.
No. The speaker (Kaal) says the roots are "above" him. In Verse 17 of this chapter, he explicitly defines the Uttama Purusha (Supreme Person) as someone other than himself who enters and sustains the worlds.