While it is possible given, particularly rich compositions, I do not advocate finding multiple photos in one photo - there are better ways in the field to achieve that end.
However, I don't understand the absoluteness of your reticence to crop for two reasons:
Firstly, since when does the world fit nicely and neatly into a 2x2, 2x3, 4x3, 6x7, 4x5 etc. rectangle? It often does or can be arranged to do so through careful composition, but it shouldn't always. That would be terribly restrictive from an artistic perspective. Nature is nature and shouldn't be "boxed".
Secondly, since when are we so perfect in our composition or decisions made in the field that we can't, upon reflection and perhaps clearer thought, alter that decision for the betterment of the photograph? 20/20 hind site is a wonderfully helpful attribute, especially when used with a clear and open mind. Painters have done it forever by altering their original vision on the canvas. It's not wrong to do so and, from my perspective, should be encouraged to free us from the restrictions (aspect ratio, sensor capture) our chosen medium (photography) might impose upon us.
Furthermore, unlike a painter, I can't, as a photographer, always pick and choose exactly what is and isn't in my photograph. When in the field, I try my best to eliminate distractions, but can;t always do so. I can choose to use this as a restriction (the "I can't possibly alter 'reality' " argument) or I can overcome the limitation by opening my mind to portray what I originally envisioned with my own artistic decisions. I am the first to advocate photographing the art inherent in nature (in fact, it is the basis of my photography), but that does't mean I rely on what I see in nature as being static and unalterable. Nature is constantly changing!
In fact, the clipped matt of moss on the water that initiated this discussion may not even be there now - it may have drifted with the current out of the frame. Or a cloud may have shaded it while still allowing the sun to pour through the moss on the tree. We are no longer shooting transparencies which are difficult to alter - we are shooting highly malleable pixels which free us to be more creative without destroying our initial intent when photographing the scene.
If your intent was clipped highlights that detract from the main composition then you succeeded. However me thinks your original intention was to portray the beautiful range of tones, details and colours in the tree moss, which the clipped matt of moss on the water only detracts from due to its brightness. But then again, to each his own.