[palmer]

Every leaf on the ground turns back into CO2 as the leaves decompose. Microbes are responsible. Ever notice how light punked firewood is? Same microbes turned it into CO2. The easiest way to figure that out is to weight the leaf litter:

https://www.jstor.org/stable/3543954?seq=1#page_scan_tab_contents The loss of weight of the leaf litter is equal to the weight of CO2 up in the atmosphere.

[JeanLM]

Leaves do decompose but the result is not 100% CO2 for sure as anyone who has a compost pile knows. Most of the weight a tree puts on in a year is also CO2 conversion into various cellulosic hydrocarbons. Burn the wood or the leaves and you get CO2. Otherwise you get CO2 bound up for a long time. After all this where the oil and gas comes from is it not?