and the forest, cunning cat, bristles its brittle fibers. (19-20)
We don't know about you, but when we see a forest, we don't think of a cat, and vice versa. This metaphorical, alternative version of the forest's reality suggests a kind of disturbance, the kind that might set a cat's hair on end. Again, the poem uses its strange, dream-like elements to communicate an emotional tone, rather than a firm reality.
But now I am not I, nor is my house now my house. (33-34)
Come again? How can an "I" not be an "I"? Or a house not a house? This kind of statement seems designed to give us a major headache. What's clear, at the very least, is that the friend speaking here is experiencing his own alternative reality, in which things that you might always trust in (your self, your intimate surroundings) have now changed. Frankly, that doesn't sound like much fun. It might also explain why the friend is unable to help the speaker when he's asked for a favor.
Tin bell vineswere trembling on the roofs.A thousand crystal tambourines struck at the dawn light. (57-60)
This is a really striking auditory image, but, well, we're at a loss as to what it really means for the poem. Know what else? So was Lorca. Of these lines, he wrote, "I cannot explain their meaning, and that is how it should be" (source). It seems that the poet was content to let the poem's version of reality supersede his own, so we are, too. For the most part.