I was reading "Birches" by Robert Frost. I am having difficulty in understanding the meaning of a line.
Please refer to this link for the full poem: https://www.poetryfoundation.org/poems/44260/birches
What is the meaning of this line:
They click upon themselves
As the breeze rises, and turn many-colored
As the stir cracks and crazes their enamel.
What does "click upon themselves" mean? Does it mean that the trees collide with other trees and exhibit a to and fro motion or does it mean that the trees hit the ground and then return back to their original position? I could not understand how "and turn many-colored/ As the stir cracks and crazes their enamel". How do they turn many colored and does "enamel" here mean the ice covering the bark of the tree or the bark of the tree itself?