This may sound like a stupid question but ...
Archeology is all about literally uncovering the past. It almost always involves digging up artifacts or evidence of ancient practices, sometimes buried under several feet of soil.
My question: where does all this soil come from? Why does all this ancient evidence always seem to sink into the earth? What natural phenomena conspire to literally bury the past?
Wind, water, and worms - predominantly.
Remember also, that most of plant growth is water, air and sunlight - only the small amount that remains of a tree after you’ve burnt it to ash is from the actual earth...so when plants overgrow something, they add organic material on top, and then collect blown dirt or mud. Then animals poopon top, and track dirt all around. Earthworms in particular keep piling little bits of soil on top of the surface.