[EGreg]

I have a question about trees:

If trees sequester carbon in their trunks and release oxygen, what do they use the oxygen for at night, and how come they are oxygen-neutral, do they store it somehow?

Also, if the Amazon is a carbon sink today, what about if there was dieback? It would turn into a carbon source, but how? Don’t the “unit economics” of trees remain the same?

[gus_massa]

Oversimplifiying: Some of the carbon goes to the wood and some goes to sugar. During the night the plant "burns" the sugar with oxygen produce energy. (If you keep a plant in hermetic place without oxygen and without light, it would die, exactly like an animal.)

(Notes about the oversimpliplification: Wood is made of cellulose that is a carbohydrate and sugar is algo a carbohydrate, they are quite similar chemically. Also, plants produce and "burn" other compounds.)