That dark tree packs a lot of punch. My eyes went right there, and the lack of detail is a major distraction. To my taste, it has to go. That being said, there is really nothing else to draw my eyes into the image. It feels like there is a significant amount of foreground missing. The ground on the bottom feels imcomplete. If you were to reshoot, the branch in the upper left is a very effective element. I would suggest moving to the left and including more foreground while eliminating the tree on the right, unless you can get some detail into those overpowering shadows.
