Suggestions requested

Here is one of the larger panoramas from the trip to Peel forest. As you see there are some major issues with it. I deliberately took images to form a step like panorama how ever I'm not exactly sure what to do with the bit's that aren't photo. In this one I've just mad them black and stuck a frame around it however it looks rather odd. So any body got some suggestions to improve the image?
And no going back to take more photos to fill it in properly is NOT and option.