Shift of Idea- "The Problem of Describing Trees" by Rober Hass

In Hass's poem, "The Problem of Describing Trees" his original idea shifts at this point in the poem: "And the trees danced.  No.  The tree capitalized.  No.  There are limits to saying, In language, what the tree did."  The rest of the poem also discusses this change in proposition, but this portion of the poem is the best example of this.  The beginning of the poem discusses the leaves fluttering on the tree and the aspen, itself, glittering in the wind, etc. etc.  This part of the poem is ridiculously "poemy."  It is so descriptive and beautiful, just like most poems are.  After all, poets are usually writers who are creative and hate academic writing, like essays.  Hass even addresses this by saying in his poem, "It is good sometimes for poetry to disenchant us.  Dance with me, dancer.  Oh, I will."  He is saying that poetry usually has an enchanting factor.  Also, this "dancer" Hass is referring to is the reader.  Hass is suggesting that poets often ask the reader to become enchanted by his or her poem.  Hass's switch in his poem is obvious because he says, "No."  At first he begins to describe the tree, and then he stops himself.  He says (in some many words) "Hello I can't describe this tree because there is no language for that I could use to describe it!"