I guess you're speaking of purely nature, and clearly I had something else in mind. There are other examples of mixed white balance in purely natural situations, for example a sunset on part of the mountain and deep shade in another part of the scene. The principle is the same, I guess I should have thought more about making the example more directly relevant.
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!