In advance I'm sorry for the kind of negative feedback, I tend to be be kind of negative and forgetting the well deserved compliments.

The shadows and lightning seem a bit akward (but so can real nature). The shadow suggests that the main light comes from the sun atop of the wolf. This makes the highlights at the legs kind of funny, or it the fur thats lighter there. The same goes for the feet, they have a white edge. Another detail about the feet is that the wolf seems to stand on the leaves as in standing on water.
Another thing is that the tail seems to be on the left side of his butt. I get the feeling that the tail should have been coming towards us a bit. If that is the case the tail should look shorter because of the foreshortening effect (I think the tail is pretty huge).
One more thing , or actually two, or maybe three lol. The shadow of the wolf is kind of a hard edge which gives the idea of a really hard lightning. At the tail the edge of the shadow can be harder, since it's closer to the floor, but the body should in my opinion have a softer edge. A gaussian blur will do I guess. And I miss the shadow of the tree in the foreground on the left side.
That tree looks a bit unnatural to me (but sometimes real trees do, especially with light from the top), I think it's because of the higher saturation, it's obviously more to the foreground, yet I can't see more details on this tree than the trees in the background.

That's for the technical opinion, now for what I think of the image:
Even though the wolf doesn't feel completely natural and doesn't blend with the background, the background is still a beautiful composition. The autumn colors are really beautiful as well, especially mixed together with the misty background which suggest is has rained not too long ago. I can basically start smelling the air.
I would have liked the image more without the wolf in it, because the wolf kinda looks out of place in the image.