Nicely composed, with wonderful colours in the sky, but something makes me feel this tree is a bit too massive to be ideally suited for a silhouette only. I myself do miss a bit of detail in it (and if that detail were black leaves which we would be able to distinguish from each other).
But that's only a feeling I have.
Since I'm all without any formal education in photography, I am not the one to give you any proper critique, ever. All I can communicate is feelings I have when I look at a photo.
And one feeling says that I do like the "waving band of clouds" that seem to blow around "your" tree!
I agree with LaFoto (Are we even allowed to disagree with her?). The other niggle I have is that the tree breaks up that nice cloud pattern; it would have been perfect had it been all to the right of the tree, but nice image nonetheless.