what kind of poem is " The Sound of Trees" by Robert Frost?

In order to determine this answer, you would have to know the difference between sonnet and free verse. The easiest way to distinguish the difference is to know that a sonnet is a fourteen-line poem written in iambic pentameter, with a rhyme scheme and structure which is determined by the type of sonnet that it is. Since this poem is longer than that, obviously it is not a sonnet. The basic definition of free verse, then, is that it is a type of poetry characterized by no real rhyme and some kind of irregular rhythm, although a discernible rhythm is there to one who knows different types of metric feet (anapest, iamb, dactyl, etc.) Frost is a well-known American writer who often uses free verse, so it is conceivable that many of his poems you would study would have this structural form. To learn more about various types of poetric feet, you can use a paper source such as Thrall, Handbook to Literature, or check out some of the reliable resources on the Internet.