Not enough of the tree seen here. If you want to shoot a huge expanse of sky like this, get right under the tree and shoot upwards, but make sure (unless it's a totally awesome sky) you got enough of your main subject to fill the frame.
That's an interesting composition - probably not something I would have been brave enough to try. It does make a real lonliness statement about the tree though - it's so small and alone in the scheme of things. Focus is pretty good (just a tiny bit blurry in the branches - but possibly unavoidable). Well done
I do not really think that this picture fits the challenge. Technically, it is sharp. The sky could be a bit more saturated colour wise. Maybe if you cropped out the top 1/2 of the photo, it would look a bit better. jgillard4
Interesting perspective, although I wish more of the tree was visible. I'm sure that there's a reason for not including more, but generally I find trees such as these interesting and I think they add a lot to the photos that they're in.