>"People look at a tree and think it comes out of the
ground, that plants grow out of the ground, " he says, but "if you ask, where does the substance [of the tree] come from? You find out ... trees come out of the air!"
How did the farmer get his donkey out of the deep ditch? He filled it in with dirt. This is just Aesop's fable. But it falls into the same abstract thinking as where does fat go, C55H104O6+78O2 --> 55CO2+52H2O+energy[0], or what happens to a tree when it burns, CH4+4O2→CO2+H2O (plus heat!)[0]. We have a hard time seeing air (sic) as something tangible. Also, this inability to visualize abstract concepts leads to political points of view such as whether or not aerosol of breath contains disease or invisible gases causes global warming.
I found this page explaining the process: https://serc.carleton.edu/eslabs/carbon/1a.html