I really like this composition. It is clean, simple and effective. However, I hope you don't mind a bit of things that might help:
1) Shot later/earlier in the day (about 1 hour before/after sunset would help bring out the warmth that is in scene but not present in the image.)
2) cropping to 4:5 aspect ratio will bring more emphasis on the foreground and the Joshua Tree. Since there is not allot going on in the sky, this will help.
