In the following essay excerpt, Wallace explores the theme of solitude in "Birches," calling it "characteristic Frost."

Frost offers us poems written in the spirit of solitude, with all of her delights. Solitude is separateness seen upside down, or from the other side, where what are sometimes felt as limits are not barriers at all. Therefore the popularity of "Birches" isn't at all incidental to Frost's central concerns. "Birches" truly is representative Frost, but in it privacy is choice, and the sweetness of the poem is genuine, the sweetness of solitude. Because Frost's intelligence is always part of feeling in his best poems, "Birches" fills us with the recognizable delight of a world inhabited only by the self, a world made by the self, at the same time that it recognizes the limits and temptations of that satisfaction. "Birches" makes a grove of privacy, creates the place...