Thanks Margie for trying. Also thanks to Pat, Kiska, Hannie and Mike for your replies.
Pat, thanks for the other view. I confirms my opinion even more that it is not photo damage on that tree. I agree that I don't know where it is coming from but the idea of a tree house in another tree could be a possibility because the lower end of the "shadow" squares off in your photo and my restore.
Hannie, the plank is really a fence post. If you look carefully you will see a wire fence attached to it.
Kiska, the area in question is from the top of the fence post on up the tree in my restore. If you are only talking about the photo Pat posted yes the shadow on the lower part of the tree is from the fence post. If you look at my restore it is taken a little more to the left where the tree and fence post almost align.
Kiska and Mike, you folks seem to be picking up something I am not seeing on my monitor about the tree branches to the left. I only found spots in that area to be corrected. The other possibility is the density of the tree branches and the age of the photo create the illusion of a stain or something that needs correcting.
Margie, I think I will follow your advice, and upload both photos that way the family can have their choice.
Again thanks for all the input.