> It's only when they photosynthesize that plants produce more O2 and absorb more CO2 than they release. And even narrower than that. I fuzzily recall seeing r

> It's only when they photosynthesize that plants produce more O2 and absorb more CO2 than they release. And even narrower than that. I fuzzily recall seeing rainforest curves, where only for some hours around noon were trees net producers. Hmm... though perhaps that was for forest-not-just-tree?