Some great images, and the crops work very well IMO.
The leaf crop makes the image follow the 3rds Rule, adding interest by off-centering the subject.
The sky/tree crop conforms the image to the "horizon 1/3 rule". Your original image splits the sky and ground 50/50, which most say is a no-no, as it's better to emphasize either the sky or ground, depending on which is more interesting. The sky in the tree shot is amazing, so the crop really works to bring it out !
As for the centered tree -- an offset could work, but I think breaking the 3rds rule to show a solitary tree also works...tastes vary
I really like the self-portrait too, excellent lighting.