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Comment by weberc2 | Hacker News Reader

> The federal effort, called the National Program for the Safe Use of Treated Sewage Water for Afforestation is going a long way towards achieving the country’s commendable ambitions voiced in the 1992 UN Rio conference on climate change—because so many trees can soak up hundreds of tons of CO2.

My understanding is that commercial forests like these don't generally capture the carbon, depending on how the harvested wood is used.

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A forest will be carbon negative regardless of how the harvested wood is used. Forests increase soil depth through dropping leaves or needles, and by light-starving prior growth. The trees also leave behind roots, a substantial fraction of the total organism weight.

The vast majority of carbon in a tree is from the air, so the sum is a net win. Most wood is also put to long-lasting uses, or made into paper which is eventually buried.

But even burning trees for power, while short-sighted, is net carbon negative, due to the first set of reasons I've mentioned.

i'm no expert but don't the roots (and everything else left behind) rot away and release co2?

Most of the CO2 is captured in soil. And there is a very good chance that such good soil will sprout other plants, continuing the carbon capture cycle. (In fact, dead trees in the forests are sometimes called tree nurseries.) So the effect is net-carbon-capture.

(I meant carbon, not CO2)

Oh, that’s great news. Thanks for setting me straight. There are so few unambiguous wins when it comes to environmentalism.

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