TL;DR
Add tree stumps and stone rock remains to the list of things that decay and fade away.What ?
When you start clearing rocks and forests to make room for expansion, graphical artifacts are left behind that never go away. These are the stumps of the trees and smaller rocky debris from the large rock you mined.In the real world, prior to building something the land upon which is to be built upon is cleared, leveled, graded and made ready to receive construction. Stumps of trees and large rocky debris are not left behind. This should be the same case in Factorio. After logging a forest and building your structures it is very annoying on a subconscious level to see those tree stumps remain there until the end of time poking through buildings, concrete, and stone pavings.