Tone

Definition:

In a poem, the tone is the kind of mood the author of the poem is trying to set. It's the voice that "reads" the poem.

Example:

I'm going out to clean the pasture spring; (light, informing tone)
I'll only stop to rake the leaves away ("only" tone - reservation)
(And wait to watch the water clear, I may): (supplementary, possibility)
I sha'n't be gone long. -- You come too. (free tone, assuring) (after thought, inviting)

Significance:

Tone in poetry is important because it let readers know what kind of emotion the writer is trying to express, and it effects the mood of the poem.