Robert Frost's Birches uses vivid natural imagery to explore the tension between the harsh realities of life and the human longing to escape them, before returning to a mature acceptance of the earth. Three images in particular carry the poem's meaning: the ice-laden birches, the boy swinging on the branches, and the pathless wood.
The image of the ice-loaded birches. The poet describes birch trees bent and bowed down by loads of ice after a winter storm. He pictures the branches clicking and cracking, shedding crystal shells of ice that shatter on the snow-crust. This image of trees permanently bowed by the weight of ice functions as a picture of how the burdens and hardships of life bend a person down. The dazzling but heavy ice suggests that suffering, though beautiful in its way, leaves lasting marks on those it presses upon.
The image of the boy swinging on the birches. Against this the persona prefers to imagine that the trees have been bent by a farm boy swinging on them. The boy who climbs a birch to the very top and then flings himself outward, riding the branch down to the ground, is an image of youthful play, freedom and escape. It represents the human desire to rise above earthly cares, to launch oneself heavenward for a while, and then to be set gently back on the ground. The controlled ride, climbing carefully so as not to fall too soon, also suggests balance and skill in handling life.
The image of the pathless wood. The persona speaks of times when life feels like a pathless wood, where the face burns and tickles with cobwebs and one eye weeps from a twig lashing across it. This image conveys the confusion, pain and weariness of adult life, the sense of being lost and hurt among tangled difficulties. It is precisely this weariness that makes the persona long, momentarily, to climb a birch away from the earth.
Conclusion. Through the ice-burdened birches, the boy's liberating swing, and the pathless wood, Frost dramatises the weight of hardship, the yearning to escape it, and the entanglements of adult life. Yet the poet finally affirms that earth is the right place for love, and the images together support his conclusion that one should go toward heaven only to come swinging back to the world.