The narrator wonders about trees, particularly the way that people willingly accept the noise of trees in their lives. Trees make constant noise about going away but always end up staying, forced to remain because of their deep roots. Their perpetual discussion about leaving is imprinted on the people around them; even the narrator begins to take on tree-like qualities as he considers the possibility of going away. Yet, unlike the trees that talk loudly and take no action, the narrator asserts that he will talk quietly and never come back.
This poem describes the everyday event of the wind blowing through the trees. The wind forces the trees to sway from side to side and rustles their leaves to create the “sound of the trees.” Frost takes this usual occurrence and, using the method of personification, transforms it into a metaphysical discussion of the trees loudly voicing their plans to leave. The wind is not moving the trees, Frost clarifies, but the trees are moving of their own accord, swaying toward freedom and then returning as they speak of their desire to the other trees.
Because of their roots, the trees are unable to fulfill their desire to leave; they are bound to the earth even as their branches reach toward heaven. Yet, as the narrator points out grumpily, they continue with their endless discussion, and their conversation is nothing more than meaningless noise to the people who hear it.
The noise of the trees is particularly dangerous because it affects the people around them and gives them the same desire to leave. As he listens to the noise of the trees, the narrator emulates their movement, swaying back and forth and pulling on his “roots” on the ground. However, the narrator does not have any roots to force him to stay. He only has the knowledge of his duty and responsibility to his community, and this knowledge is hardly sufficient to quell his desire to go.
This conflict between duty and imagination is one that Frost brings up frequently in other poems, such as “Birches” and “Stopping by Woods on a Snowy Evening.” In the rural communities of New England, duty was a primary factor in every action; the call of imagination and personal indulgence was always overshadowed by the realistic needs of the community and family. In “The Sound of Trees,” however, this recognition of duty is obscured by the endless noise and influence of the trees. Even more importantly, if this idea of duty and responsibility is forgotten, the narrator worries, there will be nothing to make people stay and build their community.
The poem does not end with the narrator choosing his imagination over his duty to his community, despite his clear desire to do so. He does, however, outline his plan to leave in the future. Unlike the trees, the narrator promises that his departure would only take place in a way that would not influence other people to make the same selfish choice. Not only will he not speak of his desire to leave, but he will also not stay to remind other people of the possibility.