"Birches" has deceptively simple name. It doesn't fill your head with huge ideas about nature or life. But the poem itself does address these kinds of ideas. The title introduces one thing – a birch tree – and then the poem becomes a meditation on the thing. That doesn't mean the poem is about birches on the deepest level. Instead, "Birches" is like word association. The speaker begins with a beautiful yet simple image, and then draws out some significant conclusions about his own life, stopping to revisit his childhood on the way. It's as if someone says "birches" and then you say the first thing in your mind. If the speaker was doing this exercise with his therapist, the speaker's therapist might tell him that he (the speaker) is obsessed with escaping from reality.