I often hear science-adjacent folks stating that a tree needs to be 30 years old before it starts absorbing CO₂, usually paired with the statement that it’s therefore pointless to start planting tons of trees now for slowing climate change.

Now, as far as my understanding goes, the former statement is very obviously nonsense. As soon as a tree does photosynthesis, it takes carbon out of the air, which it uses to construct cellulose, which is what wood is made of.
Really, it seems like it would absorb most CO₂ during its initial growth.

I understand that it needs to not be hacked down + burnt, for it to actually store the carbon. But that would still mean, we can plant trees now and not-hack-them-down later.

I also understand that some CO₂ invest may be necessary for actually planting the trees, but it would surprise me, if this takes 30 years to reclaim.

So, where does this number come from and is it being interpreted correctly? Or am I missing something?


Edit: People here seem to be entirely unfamiliar with the number. It might be that I’ve always heard it from the same person over the years (e.g. in this German video).
That person is a scientist and they definitely should know the fundamentals of trees, but it was usually an offhand comment, so maybe they oversimplified.

  • jol@discuss.tchncs.de
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    1 year ago

    That makes no sense. The human body is on average carbon neutral. You eat carbon and then you excrete it. Same as trees. Except you don’t continuously grow like a tree for potentially centuries.

      • jol@discuss.tchncs.de
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        1 year ago

        Of course it is. No carbon was created. And unless you’re putting on weight, your mass stayed the same. Carbon in, carbon out. I’m not talking about CO2 neutral.

        • CrayonRosary@lemmy.world
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          1 year ago

          Wtf? You can’t make up your own definition of “carbon neutral” and then make arguments about it on the internet.

          No carbon was created

          Yeah, no shit, but that’s not what the rest of us are talking about.

          • jol@discuss.tchncs.de
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            1 year ago

            I’m not making up any shit wth? How dense are you? A tree is carbon negative because it sequesters carbon continuously. A human adult is not, it’s carbon neutral - when observed in isolation. The human system is carbon neutral. It doesn’t matter where the car on comes from. You expel the same amount as you injest. I think honestly you’re the one who doesn’t understand what carbon neutral really means.

            • CrayonRosary@lemmy.world
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              1 year ago

              Turning carbon in the environment into CO2 by oxidizing it is NOT carbon neutral! If that was the case, then every car, plane, and coal power plant would be “carbon neutral”. That’s very obviously not the case.

              Being “carbon neutral” means that you, or the operations of your business or your national economy, emit the same amount of carbon dioxide into the atmosphere that you offset by some other means.
              (Source)

              It’s ALL about CO2! For the love of god, go read some articles. You have no idea what you’re talking about.