You see, when leaves fall off the trees, or pine needles or grasses fall over, that plant matter laying on the surface gets wet. Then wild yeasts attach to it and it begins to ferment (yes ferment). The fermentation process gives off a lot of CO2. But, this also adds nutrients to the soil that encourages more plant matter. But the new plants do not consume all the CO2, so the result is more "greenhouse gasses".
Most people don't get this, but in the USA today there are more trees than when George Washington was alive. Liberals won't allow controlled burning of forests to remove dead wood and other flammables, which also become fermenting organisms. More trees and protected grasslands result in more dead vegetation which eventually ferments making more CO2 which, by the way, encourages more plant growth.
Used to be a good lightning storm would take care of "controlled burn". But now, one puff of smoke from the woods and 2,000 people are out fighting the "deadly wildfire", go figure. I'll stick to my 4th of July steak.