Great composition! I assume the grayness is from fog, but did you try increasing the contrast & brightness until the gray became white? I could see that working even better...
For me, what makes this image a 10 is the sign. I'll bet you get comments telling you you should have cloned it out. If you do, I disagree. This lonely island, in the middle of nowhere had a person think it was important enough to put up a sign. As a viewer, I can imagine this sign says anything and that adds so much to the image. Right now I'm in a humorous mood so the sign says, "No Swimming." I love that there is just enough reflection to show me water. And the reflection shows how the tree could have grown (the reflection is straight). I love the 'bentness' of the tree - it grew in its own funny way even though there was seemingly no reason for it to do that, nothing impeding its growth straight up. And its leaning towards the sign, as if for comfort. Okay, I'm odd. Profound is the word I keep coming up with. I have been trying to create images that are poems. This is one.