Please help me, is "Dreams" a free verse lyric poetry? What's its meter? And its tone?

Langston Hughes'' short poem "Dreams" is a lyric poem, yes, but I'm not sure that I'd call it free verse. Read the poem slowly out loud:

Hold fast to dreams
For if dreams die
Life is a broken-winged bird
That cannot fly.
Hold fast to dreams
For when dreams go
Life is a barren field
Frozen with snow.

You'll hear the structure clearly enough. When I think of free verse, I tend to think of poems that don't have such a clear structure (in both meter and rhyme). Hughes' poem is written more or less in iambic dimeter, as seen most clearly in the line "That CANnot FLY" (the two stresses of the dimeter are written in all caps here). Lines 3 and 7 probably have to have an additional stress. Iambic is pretty much the meter, given the closeness between Hughes' poems and spoken English; spoken English tends normally to fall into iambic meter.

The tone of the poem may be a little complex. In the repetition of the line "Hold fast to dreams," I get a sense of hope and urgency, but the imagery -- particularly the "broken-winged bird" and the "barren field" -- gives me the sense of failure, of promises and potentials unfulfilled.