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.

      • @Squirrelsdrivemenuts
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        61 year ago

        It is probably a statement related to the average tree. Also, I believe hemp and bamboo are not trees (but I’m also not a plant scientist) so not really relevant in a statement about trees.

        • @[email protected]
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          1 year ago

          Bamboo is a grass, I think hemp is as well but I can’t speak to confidence with that one.

          Edit; I looked and best I could find was that cannabis is an herb

          • 【J】【u】【s】【t】【Z】
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            1 year ago

            Ehh, cannabis is a woody annual. At least that’s what I’d call it. It dies every season. In some places a stand can reseed itself or a mother plant or two may overwinter for a maximum of one season by being buried under it’s daughter plants after they collapse from senescence, essentially cellular death from old age, which varies by species.

      • @[email protected]
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        61 year ago

        I think there has to be a certain balance. We can’t just cover a massive field even in trees, that creates an unhealthy ecosystem.
        Sometimes, as we try to fix things quickly, we miss or ignore the long-term consequences.

      • @count_of_monte_carloM
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        61 year ago

        Hi there! Can you please remove the word “retarded” in your first sentence? This word is now generally considered a slur, which runs afoul of rule 6 “Use appropriate language and tone. Communicate using suitable language and maintain a professional and respectful tone.”