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.

    • Hyperreality
      10•1 year ago

      Not your fault, but that is the most annoying calculator I’ve ever encountered, as someone who uses the metric system.

      I mean, what kind of maniac describes the amount of oxygen produced in pounds?

      Also are those US gallons or UK gallons?

      The increments used for the circumference of the tree is also incredibly weird, 7 and 3/4 inches? Really? Clearly converted metric to imperial. Why not include a slider to switch to metric, if that’s what you’ve based your numbers on?

      • @FlowVoidEnglish
        2•1 year ago

        It’s a website written by an American for an American audience, which means the writer uses inches, pounds, and US gallons.

        No need to feign surprise that Americans generally don’t like the metric system.

        • Hyperreality
          4•1 year ago

          7 and 3/4 inches is (roughly) 20 centimetres.

          Why not use 10 inch increments or even 6 inch increments if you’re making a site for an American audience?

          It’s like car sites and manufacturers which list the 0-60 time, but it’s actually the 0-62.14 time.

          If you’re going to use imperial, use imperial. Don’t do a half assed conversion from metric.

          I am also available if anyone wants to listen to a rant about ecoflush toilets.

          • @FlowVoidEnglish
            1•1 year ago

            Probably because the writer is not reporting her own original research. She is reporting work done by others, they often used metric, and any metric units were converted to common US units because the article was intended for a general American audience.

            And why isn’t there a button to restore the original metric units? Same reason why when a newspaper reports a translated quote from Macron or Putin or Xi, there is usually no button to restore the original French or Russian or Chinese: the editor decided that it wasn’t necessary for the intended audience.