pine tree

I think isolated trees are a great subject, and you've got a good one here because it's on the crest of a hill.  Isolated trees, IMO, are best shown in context of a larger surrounding so that the idea of "isolation" can really be seen.  I'd suggest that you zoom out (or back up) so that you get all of the tree and more of the background countryside, raise the camera to show a bit less foreground and so that you don't crop the cloud right above the tree.  I think you seldom want to crop a tree like this, and if possible you want to avoid cropping a main cloud (especially a very small portion of an otherwise complete cloud).  Your horizon might be sloping down to the right, although that's sometimes hard to tell; the angle of the slope, the tree, and the background landscape all suggest that to me.  I think those changes would help to capture the concept of an isolated pine tree.  My $0.02.

you found a fine subject in a beautiful landscape with nice sky.  Cutting off parts of the tree and even the cloud are not helping the photo, though.  I agree with the comments above - zooming out a little bit would help.  Cheers, Micheal