Great foreground detail, love the triangular wedge of blue sea and the tree is a simply fascinating subject. For once the empty sky is just perfect for the shot.
I think its a litle underexposed but that´s maybe intentional to give better expression of what you are trying to say there. Have you tried to convert it to B&W and maybe make it still more darker and increase the contrast?
i think this would have been stronger if it were a landscape, and i'm unsure of the exposure you've chosen..its not doing very much for the sky or the water. They both look bland.