"The Tree of Song" seems to be addressed to a person of great influence to the speaker. The speaker says plainly, quietly, and with a tone almost of awe that this person in question has stripped away all that is superfluous about the speaker and revealed her very core, "the tree of my song." Below is a line-by-line take on the poem.

"I sang my songs for the rest, / For you I am still." The speaker's "songs" or "leaves" seem to be extraneous to her existence. They are nice, and she produces them (perhaps the way a poet produces poems?), yet they are not essential to her being. They are easy to give away. So, the speaker sings her songs for "the rest," for other people, but for the subject of the poem, she has more reverence and interest: "I am still."

"The tree of my song is bare / On its shining hill." This somewhat plays off the expression "to bare one's soul," which means to open up and reveal one's true self, thoughts, or feelings. The speaker's soul, or "tree of song" is open and visible or "bare" to the subject. Moreover, we know it's a positive thing, because the tree sits on "its shining hill," which seems to be a bright, peaceful place where it feels at home.

"For you came like a lordly wind, / And the leaves were whirled." The speaker tells the subject that they entered her life in a masterful, commanding (though not overly demanding) way. The subject's presence in the speaker's life was so powerful and compelling that all the less important matters were whisked aside: "the leaves were whirled."

"Far as forgotten things / Past the rim of the world." The "leaves," or the everyday material of the speaker's life (perhaps words or objects or obligations) fly far from the speaker. They move to a place so remote they are now "forgotten things." The power of that "lordly wind" was so great, it moved all these things "past the rim of the world."

"The tree of my song stands bare / Against the blue—" The speaker repeats the line from earlier, "The tree of my song stands bare," to emphasize just how stark, how new is this change in her life. As though to light up in our minds the silhouette of that bare tree, that bared soul, the speaker tells us it is "Against the blue."

"I gave my songs to the rest, / Myself to you." The speaker's "leaves" or "songs," those expendable parts of her life, she gave to everyone else. Her self, her "tree of song," her most precious possession, she gives to the subject of the poem: "Myself to you."