What is the overriding theme of "Our Casuarina Tree" by Toru Dutt?

I would suggest that the
main theme of this poem has to do with the existence of a harmony between human
beings and nature. The tree is associated with the animals who live and play in
itthe baboons and the kokilasas well as the cows that enjoy its shade. The tree's shadow also
covers the body of water beneath it, where water lilies grow in such great number that they look
like snow. The speaker goes on to describe the way she and her "sweet companions" used
to play beneath the tree's boughs. The tree rises up in her "inner vision" and brings
her happiness and peace, perhaps because it does symbolize the union of nature and humanity,
achieving a unique kind of beauty, meaning, and innocence. Many descriptions make this tree's
home sound like the Garden of Eden, but there is no tragic fall from grace to be had here: the
snake is only a vine wrapped around the tree that is covered in flowers. Grace survives as the
tree brings all beings together in harmony.