Cottonwoods in Zion - Zion National Park

What is most distracting to my eye in this photo is the non-uniform sky brightness, that seems to follow the outline of the treetops. The actual brightness of the sky background, of course, should not be related to whatever happens to be in the foreground of the photo. I presume the brightness enhancement at the ends of all the tree branches is an HDR effect you were after, but if possible to prevent the HDR effects from spilling over into the sky background, I think it might be more effective (as besides being more uniform, the sky would also be somewhat darker behind the tree branches, accentuating the brightening of the branches themselves).

The hand-drawn yellow curve in the image attachment below (magnified screen capture from your image viewed larger) traces one of the contours in the sky background that my eye finds distracting.

Good luck !

... is the tree trunk in lower left whose bark goes from light to dark along the horizon-line boundary of the mountain in the background. Coincidence, or (more likely) an unintended result of HDR ?

Thanks Jim, I'll definately have to take a look at the sky color issue, that was the part of the HDR composition I liked the least but I was trying to make the branches be highlighted in the sky. Here is one of the exposures straight from the camerahttp://gallery.photo.net/photo/7058716-md.jpg

It turns out that the tree really just happened to naturally change colors along the horizon but I agree it is unnatural looking too and might need a little selective darkening there.I'm going to have to go back and see if I can recompose the same photos with less of a sky distraction but keeping the branches highlighted.