ice and snow for long periods, so that they remain bent even when the spring thaw arrives. Ice-storms are impersonal—unlike the child, they are not deliberately bending the trees—but their effects are permanent. So may a person who has endured a lengthy period of difficulty find himself permanently altered by the burden he once bore.

Frost acknowledges the lasting impact of the changes wrought on the trees, but he implies that the trees still have the spirit of youth and innocence within them. By comparing the birches to "girls on hands and knees that throw their hair / Before them over their heads to dry in the sun," Frost is showing the bent posture of the birches as both temporary (the girls will not forever remain on hands and knees) and practical. This is a kind of deception, because the birches will never rebound from their position, but perhaps what Frost is saying here is that the innocent spirit of the trees remains, even if it is now warped in some way by the changes of experience.

The ice-storms that affect the trees may be compared to the "trackless wood" an adult can find himself struggling through in particularly difficult periods of his life. Frost deftly evokes the torment of life's myriad demands and distractions in the burning and tickling of "cobwebs" and the tears that flow from an eye across which a twig has snapped, making the walker part-blind and increasing the difficulty of his movements. When life feels like this "trackless wood," the innocent joy of the birches of childhood is nowhere to be found. Rather than moving through nature easily and taking pleasure in it, the adult stumbles heavily, confused, frustrated, and pained.

Frost wishes he could escape that situation as easily as the young boy earlier in his poem swings the birches. He simply wants to "to get away from earth awhile / And then come back to it and begin over."

Robert Frost often includes natural imagery in his poems. His intent is usually to show how closely man is bound to the natural environment in which he lives. Other frequently studied poems like “The Road Not Taken” and “Stopping by Woods on a Snowy Evening” are completely constructed around images of the speakers' immediate environment.

The first simile in the poem, “like girls on hands and knees,” comes about a third the way through the poem:

You may see their trunks arching in the woods 
Years afterwards, trailing their leaves on the ground 
Like girls on hands and knees that throw their hair Before them over their heads to dry in the sun. 

Part of Frost's aim has been to show that the birches are vulnerable to the effect “swinging” by boys. This vulnerability is emphasized by comparing them to girls—the trees are delicate, like the girls, but also beautiful in their way.

The second simile comes about two-thirds through the poem. The poem has evolved by this point—Frost has become more serious. In this simile, “like a pathless wood,” Frost is saying that sometimes life becomes difficult, filled with worries and decisions that have no clear answer:

It's when I'm weary of considerations, 
And life is too much like a pathless wood
Where your face burns and tickles with the cobwebs 
Broken across it, and one eye is weeping 
From a twig's having lashed across it open. 

He uses the simile to compare the physical pain of being cut by a twig to the distress caused by life's cares, and goes so far as to suggest he would like to “get away from Earth awhile.”