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Comment by onion2k | Hacker News Reader

A mature forest doesn't remove much CO2 from the atmosphere. A growing one does. Depending on what you do with the felled lumber, it could be much better for the environment to chop down a forest and plant a new one.

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A mature forest not only hosts diverse ecosystems, it also produces a beneficial local climate.

It's also a gross oversimplification to look at CO² balance by absorption by trees only. Floodplain forests, forested swampland and broad-leafed trees also store massive amounts of CO² even when the forest is mature.

But more importantly, mature and healthy forests offer a broad range of benefits beyond binding CO². Reducing the value of forests and the associated ecosystems to CO² is a flawed approach. There's many more factors involved, including preservation of fresh water.

>CO²

Nitpick here: I see you've gone into the effort of stylizing the 2, but chemical formulas are supposed to be numbered using subscripts, not superscripts.

CO₂

This is a non intuitive result, and people is confused often by that, but adult mature [1] trees grow much faster than young trees. Faster here does not mean taller, means bigger.

[1] I'm not talking about dying trees, mature does not mean dying necessarily.

A mature forest isn’t just filled with mature trees you get the full lifecycle and close to zero net carbon capture.

It’s not obvious when walking around because adult trees significantly outnumber dead ones, but trees decay in a tiny fraction of their total lifespan.

Decay can sequester carbon in the right ecosystem and physical geography. Western Europe has its topsoils thanks to centuries of wild mature forest.

Do you have a source, both ways seem to have some logic to them (a larger growth is a smaller percentage growth for a large tree, for example - adding 1% to a massive tree is better than 10% to a tiny tree), but also we're used to new life increasing size far faster ...

Actually, I might tree rings not getting smaller as a tree grows taller is probably enough evidence to see that the carbon added increases over time? Would be nice to have a rigorous source to review too?

do you have some science to back up this claim? i’ve read a bit about this as an layperson and the mature vs young forest debate seems kinda inconclusive. but it also seems like keeping a mature forest’s ecosystem in tact is better than clearcutting and planting new trees that supposedly grow faster and capture more carbon. by clearcutting, you’re removing and releasing a lot of the ecosystem (mushrooms and such) that also play a part in carbon capture and storage. capturing carbon is only one part, from what i understand, a mature forest’s ecosystem does a lot to retain it, too.

Maybe the middle way should be not clear cutting but punctual culling so you'd try to get best of both worlds... and getting closer to regenerative agriculture as well.

'grow faster' is a bit of a vague statement. What we should be talking about is biomass added, which is what sequesters carbon. Older trees unequivocally add mass at a faster rate, which is geometrically obvious when you consider that old growth tree rings add about the same radius each yeah that young growth trees do, and then consider that area of a circle grows with the square of radius.

see:

https://news.unl.edu/newsrooms/today/article/study-finds-lar....

That's such an incredibly short-sighted and single-tracked view on what is "the environment". Planting trees will not magically fix the climate, and carbon sequestration is not the solution to all our problems. Destroying ecosystems for the sake of capturing more carbon makes no sense, if for no other reason that it reduces the chance of survival of the new trees. You also can't lose focus from the end goal of why we're trying to capture CO2. The goal is to save the environment.

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