For those who are interested in entering competitions sanctioned by the PSA and other international societies. The PSA standards have been adopted as the "Gold Standard" and they are very specific as to what's accepatble.
If you have the time they're available at https://www.germanphotocup.de/files/jahre/Dateien/Nature Photopgraphy Guide 2022-15Sept21.pdf (from a German salon)
At least they are specific and clear. Don't clean up a twig or a bit of trash, among many other restrictions. This cut and pasted section I found interesting. No roads, no mowing, no power poles, etc.:
SOME HUMAN-MADE THINGS ARE NOT ALLOWED IN NATURE IMAGES.
Nature images are not allowed to contain people or things created by people unless the objects are a
necessary part of the nature story (as described in the previous section). Examples of things that
have been created by people of modified by people and are not allowed in nature images include but
are not limited to:
o Roads, paths or trails that are not a necessary part of the nature story.
o Vehicle tracks.
o Fences that are not being used directly by an animal or bird as part of the nature story.
o Signs.
o Power poles and wires.
o Vehicles.
o Buildings or parts of buildings that are not being used directly by an animal or bird as part
of the nature story.
o Walls or parts of walls.
o Cultivated farmland or mowing and ploughing patterns in fields.
o Cut tree stumps, cut-off limbs, branches or stems that are not a necessary part of the nature
story.
o Jesses and thongs on legs of raptors and other birds (these are not scientific banding).