In "To Return to the Trees," Walcott reflects on the process of ageing, death, and man's connection with nature. These are the main themes in the poem.

The speaker, in the third stanza, wonders what it will be like "to decline like. . .this burly oak." In the fifth stanza, he imagines himself, fondly, as an old "gnarled poet, bearded with the whirlwind," but he wonders too, in stanza four, whether he really is looking forward to old age, or whether he is "lying / like this felled almond." In the seventh stanza, the speaker says that "gray has grown strong to (him)," implying that he associates old age with strength, perhaps meaning a strength of character rather than a physical strength. He continues, in stanza eleven, to describe gray, symbolic here of old age, as "the heart at peace, / tougher than the warrior."

At the end of the aging process, of course, there is death. In the first stanza, the speaker speculates that death might mean a "return to the trees." The implication here is that in death he shall return to the soil, or to the earth, just as the trees will when they fall. There is a sense here that man is simply a part of nature, derived from and inevitably set to return to nature. In contemplating death, the speaker thus also contemplates, at the same time, his connection with the natural world. He emphasizes this connection throughout the poem by drawing parallels between his own ageing process and the changes he observes in nature. For example, in stanza six, he observes "the changes on Monte Coco Mountain," and he observes too, in stanza seven, the path of the sun across the sky, "from flagrant sunrise / to its ashen end."