Hi Daniel! Looks like a nice morning.
First thing I noticed when I looked at your post is that the lack of sharpness in the tree was probably not caused by camera shake.
Because, as a general rule, your shutter speed should be as fast as your focal length to stop camera shake. So a shutter speed of 1/20 of a second should prevent camera shake at a focal length of 18mm.(or 1/500 of a second for a focal length of 500mm). And that does not figure in IS(which your lens probably has). 1/40 or 1/50 should have easily stopped any camera shake, even without stabilization!
I would guess blur was more likely caused by wind or focus.
But then that raises a question of my own, if your camera has a crop sensor(like mine does), do you have to figure that in for stopping camera shake?
Good job with the camera settings! Looks like what I would use. =) Although if you would have had your tripod, I may have stopped the lens down more.