First question did you use RAW or JPEG?
I don't think personally you had enough exposures for this photo. Your brightest picture is not that bright for details in the shadows.
After processing it a few times different ways I have realized that the issue is in your actual photos and photomatix amplifies it at least using these low res jpegs you posted. I would like to use your high res originals if you want to email them to me @
vipgraphx@cox.net
Sure you can move the highlight smooth alllll the way to the right but then it blows out your whites in your clouds and other areas. I also messed with the strength slider which helps a lot keeping it lower than 70% along with adjusting the micro smoothing moving it more towards the middle. This really seems to help. I also notice that these are not aligned. Did you hand held these shots? If you used a tripod go buy another one because these were really off. This also will influence the streaks in the sky believe it or not. I also notice your sensor was really dirty there were a bunch of dust spots I saw. The problem with this is that you can not go crazy with this photo because the detail is not there and if you do it will show the banding/streaks in the sky so you have to be more subtle on your sliders. Adjust the light slider and luminosity also work.
So I think it's in your actual photos and processing combo. Keep in mind that photomatix is just to get you 50-70% done and photoshop is to finish it off.
Here is a really quick edit I did. All though I did use the smoothing slider all the way to the right.. it blew out the white in the clouds and that highlight in the leave area. So I had to use the original exposures to fix that. It was somewhat flat from photomatix so I adjust contrast and then you can start to see that area again in the sky. Not as bad but since you know its there you can see it a little.
Here is another edit with the smoothing all the way to the right, then adjusted strength to 70% and micro smoothing to 4. I adjusted the lighting to the right a little. Then I masked in the blown out highlights in the clouds with the original files. NO streaks...
like I said if you would like to email me the original exposures I can see if I can do a better job and hunting the problem dow. But, for now I need to know were these jpeg or RAW?