It would have been better to have the man and his dog to the right where you have some nice negative space instead of right in front of the tree where they blend and blur. 4
I like the idea behind this shot. The problem is that your subject seems to merge into the pine tree behind so it is hard to tell if there is anything there. I think it would have more of an affect if they were to the right or left of the tree. The tone of the image is perfect.