Ole, this is a classic example of trying to combine a group of elements that don't always play well together. In fact it can be tough to pull it off. I think you did well, taking all of this into consideration!
I agree about foreground Aspens being a bit dark due to shadows, but it's by no means an issue with the overall image. One option would be to use a larger aperture, since it can allow a bit more light reflectivity on the tree trunks that are in shadow, since the Aspens' trunks are very bright compared to most tree trunks. Instead of F/8, try F/7.1 @ 1/180 sec. ...
Another option is to consider using a GND filter on the skies, but that's another tough spot to deal with since a lot of experimentation would be needed.
Regards,
Marc