I feel a bit guilty about what I want to suggest, but this is a great image which I believe has a slight problem.
I'd suggest to crop away a part of image, be it from the bottom, the top or both.
My impression is, that the very dynamic format takes something away from the otherwise very beautiful image.
So I want to suggest - not to make is square, but maybe a little more "squarish".
I am not sure if this would work if it was printed big though.
Cheers
~Chris