Hi Joanna,
I love the play of the morning light in the dark and light areas of the trees as well as the rising steam. Originally I was going to say that i would have preferred the buffalo a hair lower in the frame........but it isn't merging with the boardwalk and it balances well with the opening in the steam where the light is hitting the evergreeens. I've eyed a slight crop off top and bottom............but there is nice texture throughout..........so it isn't necessary but more of a personal choice. Getting up early definitely paid off nicely for you.
This is a really powerful image with the well-place bison in a beautiful steam-filled scene. Like Roman says, getting up early was the right move! I particularly love the way that the low early light has reached some trees and not others. Beautiful!
Nicely done, Joanna. I think Roman is right that a small crop off the bottom might work better - totally up to you. I wonder, too, if you could pull a few of the shadows up in the BG...not much - just a bit more detail back there might be nice. Lovely image!