Perhaps the first two stanzas represent the secret to which the speaker refers in the third stanza. Perhaps the speaker’s love is this secret, which is also replicated in nature. The speaker refers to a tree called life, which grows higher than the soul can hope of the mind can hide. So high, too, is the love of the speaker. Just as life and nature go on for infinity, so does his love. Whatever the immeasurable thing is in nature that keeps things growing and living, that keeps the stars apart from each other, it is the same as what lies in the heart of our speaker.
here is the root of the root and the bud of the bud
and the sky of the sky of a tree called life; which grows
higher than the soul can hope or the mind can hide)
and this is the wonder that’s keeping the stars apart.