Because he would not be discriminated — the birds will not ask his caste to build the nest — Sunrays don't run away — feels happy with the touch of sacred cow — gets opportunity to shelter three hundred thousand Gods — becomes pure when burned by holy **** — satisfied in becoming a bier to the sinless body.
Detailed Answer :
The poet wishes to become a tree because then he would not be discriminated. The bird wouldn't ask its caste to build the nest, the sunlight won't run away, it would rather embrace it. It can do friendship with cool breeze and rain drops wouldn't go back by thinking that it is untouchable. The tree would feel happy with the touch of sacred cow and it would get the opportunity of providing shelter for three hundred thousand Gods. It can become pure if it would be cut into dry pieces and can help the sinless **** body by becoming bier on the shoulders of four good men.
