> Old growth plateaus from a ton/acre of carbon perspective pretty quickly, and old growth forests aren’t meaningfully sequestering much new carbon in their soil. It reaches a steady state, with excess rotting. Almost no forests do, or they’d be sitting on hundreds of feet of charcoal like matter.
> New growth pulls carbon out of the atmosphere fast - and cutting it down and using it, gives room for more, fast.
Once it reaches this steady state, how much carbon has it already stored? How long will the average undisturbed old growth forest remain at steady state? 200 years, 1000 years? 10000 years? Surely longer than the average lifespan of all the products a destroyed old growth forest might produce. This is especially true when considering that old growth wood is particularly valuable for use as biofuel due to its high carbon density. This means that that carbon will be released far sooner than it otherwise would have, likely magnitudes sooner. And it says nothing of the carbon that doesn't even make it into a product. The simple act of killing the forest and turning over the soil will immediately release carbon.
But, you might say, we'll plant new growth and that'll absorb carbon at a faster rate than ever. Is that rate fast enough to account for the early release of the old growth carbon? How many cycles will it take to recapture that carbon?
> Even the best of them it’s less than 6 feet of carbon containing soil.
So? Is that an average for old growth forest soil? How does it compare to new growth soil average? A single measurement is meaningless here.
More importantly, what is the comparitive density of the carbon in the soil? Depth of carbon-containing soil without a density doesn't tell me much about the total carbon stored.
> the math is clear and easy to verify.
If you say so, but unfortunately you didn't provide any math whatsoever. You seem confident though so if you have any sources, then please do share. I did a quick search for various numbers and comparisons and the numbers don't look good for your argument unless you are only comparing the rates at a given moment and ignoring the total sequestered carbon over a suitable time range (there's probably a better description for this...something like average years of sequestration for any given carbon atom during the average lifespan of an undisturbed old growth forest vs the same tract of land cyclically harvested and replanted at a profit-maximing rate over the same time period)
Most of these products do actually end up sequestering carbon nearly indefinitely, as unless the house or structure burns down, the product ends up in the landfill or remains on site. Unlike forest products on the forest floor, they don't naturally decompose - we protect them to stop that, as a side effect of how we use them.
Because it is usually pretty well protected, and doesn't meaningfully decompose. Even in most (sufficiently old) landfills, you can dig up newspapers from the late 1800's and still read them. When people print things out, the vast majority of them end up shredded (and tossed in the trash), or just tossed in the trash - which ends up landfilling them, etc.
Once landfilled, what decomposition does happen can be mitigated by processing/burning/storing what methane and the like does come off them.
You're confusing carbon storage (as in total retained) with carbon flux (as in net amounts in/out). Something that old growth folks intentionally also do (first link), near as I can tell, to specifically confuse the issue. If you read carefully you can see them stepping around the issue in the first link I pointed you too.
TOTAL carbon starts to plateau relatively quickly, even as noted by old growth proponents - with total carbon flux dropping and eventually being roughly at equilibrium - usually well before we even consider a forest 'old growth'. If you look at the charts in the second link, you can see the actual curve.
Peak flux (as in total negative carbon) is usually at around 15-20 years.
I'm not proposing we cut down all old growth forests. That would be ugly and counterproductive.
Rather that making a forest that has already been cut down be untouched until it becomes old growth is not the most efficient way to reduce carbon, if we're trying to use forests as carbon sinks.
Be aware however, I've done the math before and even if we turn ALL potentially forestable AND farmable land into forests, it is impossible to sink all the carbon we're currently emitting into forests. Not even close, unfortunately.
But if land has already been harvested (which most has), the more efficient way to reduce carbon is a decent amount of turnover where the products end up going into either durable goods, or landfilled products.
I love trees, and spend a lot of time in nature. I've also done the research, and looked at the reality in front of me, and it's hard to ignore.
It also states [1]: "On sites like Fairy Creek, old forests are estimated to store twice as much carbon as mature forests and six or more times as much as clearcuts. Productive coastal old forests can store up to six times more carbon than old forests in drier climatic areas."
In that quote "productive" I think means mostly a mature forest (in other places it is noted that only a fraction of area is available for logging, so it's not quite clear what exactly productive means).
From the table of sequestration - it's very interesting how much carbon is sequestered into the ground compared to above ground. Old growth put a lot more into the ground, while new trees sequester almost entirely above ground. The numbers are very different too... The old growth, per same unit area, have a lot more sequestration compared to regen and immature forests.
> Be aware however, I've done the math before and even if we turn ALL potentially forestable AND farmable land into forests, it is impossible to sink all the carbon we're currently emitting into forests. Not even close, unfortunately.
A lot of land cannot be forests. I know this wasn't quite your point - but one thing I think missed by the "grow forests to chop them down and bury them" - is that when a forest is chopped down it no longer is fire resistant. A person can only do that for so long before an intense fire comes along and turns that area into a savannah. The growing trees have no chance, they all burn down - this is how forests become savannahs.
I truly appreciate your comment and the dialog here!
Edit: fuck it, I’ll just do the math again. See the bottom.
They keep confusing the issue because they keep talking about storage. Because their underlying motivation is to have more old growth trees, and to pull carbon from the atmosphere as a secondary effect. Which hey, I get, they’re beautiful. But it’s still BS to say old growth is extracting carbon from the atmosphere faster than new growth.
To see for yourself, use that table they made and take ‘estimated total carbon’ and divide that (tons) by the estimated stand age. That gives you tons of carbon per year of stand age. The really old growth stands with the impressive (overall) carbon numbers actually have really terrible (relative) tons/year numbers. Like the first one is ~ 2.3 tons/year. Where if you go to the new growth stand and ignore year zero (because that has a super high number/divide by zero), it’s 13 tons/year. About ~6 times higher.
And note, it has to be that way. If you took the rate from the new stand, and multiplied it by the stand age for those old stands, the whole forest would have to be solid carbon with no air or gaps.
And unlike those old growth stands, the new growth stand is also producing useful-to-humans output like lumber as part of that calculation, where old growth stands will be nature preserves in this calculation.
In my experience, it’s useful to think of forests like a carbon ‘spring’, or even dam. They aren’t (generally) sequestering it the way the word tends to bring to mind (locking it in a warehouse somewhere maybe). Wood wants to burn in our atmosphere, especially dry and dead wood. If enough of it builds up, eventually that spring will release, or dam will break/overflow, and that carbon goes right back into the atmosphere. Usually in a catastrophic fashion.
Harvesting it and putting it somewhere it won’t rot is like releasing that spring or the water in the dam, without breaking anything.
Regarding your comment on chopped down forests not being fire resistant - it’s actually the other way around. Non-existent trees and brush can’t burn.
Additionally, not harvesting timber from most forests results in overgrown and sick trees, which are a nightmare forest fire wise. It’s why california (and other western states) keep catching on fire so badly, because logging has been so heavily restricted. I’ve done thinning work, and it’s night and day from disease and fire risk. Almost impossible to burn a forest after it’s been done, and it doesn’t want to.
Before that, it was a complete tinderbox.
Now don’t get me wrong, clear cut logging followed by terrible replanting and management practices are certainly be worse (fire wise) than just letting an old growth forest be. Especially since those tend to be in consistently very wet areas that don’t like to burn. But that isn’t how it’s been done in a long time, outside of perhaps random bandit operations.
In California’s climate, it requires cutting down a significant portion of trees and removing built up brush (or doing a controlled burn), or the whole thing turns into a mini-nuclear explosion waiting to go off.
Also, most of their numbers actually seem weird to me though, because as far as I’m aware, more independent data actually shows even newer growth at more like 1.5 tons/year on average across the US.
Edit - here comes some math (different links this time)
Ok, so the US Forest service says that research shows forested land in the United States sequestered 775 million metric tons of carbon/yr [https://www.fs.usda.gov/research/sites/default/files/2022-04... ], and also that the US has 819 million acres (approx.) of forested land.
Which is approx. 1/3 of all US land cover.
Notably, I don’t think that is discounting carbon released due to wildfires in those lands, but I might be mistaken.
That also works out to (on average) 1 metric ton of co2 stored per acre per year on forested land in the US.
If I remember correctly, another 1/3 of the US by landmass can be considered arable (there is overlap), aka can grow things, with some work.
That means all US forested land sequestered enough carbon to represent a little over 10% of one years co2 emissions per year. Doubling all US forestland would therefore account for around 20% of each years co2 output.
If we figured we could double again efficiency by using fertilizer, etc. we’d still be stuck at only 40% of each years co2 output. And we’d starve, because we converted all our farmland to forests and those trees are generally not a good source of nutrition for humans. Also, we’d have to kill all the cows/pigs/etc.
So barring turning every forest into some sort of super productive co2 farm somehow, and converting all available fertile land in the US to do it while somehow not starving to death - I don’t see how we’d even pass 50%. And even then, I wouldn’t take that bet. :(
That hopefully also provides a more useful idea of the scale of the addiction humanity (and the US in particular) has with fossil carbon, when we’re digging up and burning the equivalent of 10x the rate our forests grow, every year, and we’re one of the top 10 most forested countries in the world.
Thank you for the reply. I plan to re-read it a few times and go into details tomorrow. I appreciate the effort and will look through it.
Meanwhile, a few quicker responses:
> Regarding your comment on chopped down forests not being fire resistant - it’s actually the other way around. Non-existent trees and brush can’t burn.
True, but if we are trying to regrow a forest to capture the next round of resources & sequestration benefits - that area has to go from being a non-forest to a young forest. During that time it's very susceptible to fire. Even worse, if the area is being re-grown as tree farm, AFAIK it'll never become fire resistant.
Though, really the question is how do you continuously regrow trees and never have the area eventually burn and turn into a savannah? Given so much forests have been chopped down a few times since the 1800s in California. We are looking at maybe 2 to 4 rounds of trees being chopped down and regrown. Lots of younger forests create a component for larger forest fires.
> It’s why california (and other western states) keep catching on fire so badly, because logging has been so heavily restricted.
My understanding is fire suppression is more to blame. I'm curious where exactly our views differ & why.
For tinder box fires, I think it's a bit more complex than one factor & the combination of factors is not good. Essentially, forests were logged with impunity and at mass scale (still kinda true today) for a few hundred years, then in North America we started fire suppression on an industrial scale circa 1950. A lot of forest is young'ish and/or doesn't have the same fire resistance as what was before it - and combined with mass fire suppression & young'ish age -> it's a huge tinder box.
Though, you point to the lack of logging as the cause for the tinder box. To what extent would you say fire suppression has played a role in current western fires?
I'm a bit surprised we might disagree here, perhaps I'm ignorant how logging has kept the situation in check. My very (tersely stated) impression of things is essentially Europeans came, logged the crap out of the area, stopped letting the fires burn 70 years ago because we could do something about it and secondly there were then enough people in the area to care. Fast forward, the west coast is now very populated and the forests are kinda young and are regrowing in a full fire-suppression environment. Do you disagree with that (frank) assessment?
> In California’s climate, it requires cutting down a significant portion of trees and removing built up brush (or doing a controlled burn), or the whole thing turns into a mini-nuclear explosion waiting to go off.
I agree. Otherwise when a fire does comes through, it will potentially turn the area into a savannah (mini-nuclear explosion'esque). I've seen a few examples, it brings back memories. There certainly are forest fires, big ones, then even bigger ones that damage the forest, and then there are the ones in California that remove the forest..
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Again, thank you for digging up numbers & references. I want to go through those in a bit more detail before sharing any thoughts/questions
Once it reaches this steady state, how much carbon has it already stored? How long will the average undisturbed old growth forest remain at steady state? 200 years, 1000 years? 10000 years? Surely longer than the average lifespan of all the products a destroyed old growth forest might produce. This is especially true when considering that old growth wood is particularly valuable for use as biofuel due to its high carbon density. This means that that carbon will be released far sooner than it otherwise would have, likely magnitudes sooner. And it says nothing of the carbon that doesn't even make it into a product. The simple act of killing the forest and turning over the soil will immediately release carbon.
But, you might say, we'll plant new growth and that'll absorb carbon at a faster rate than ever. Is that rate fast enough to account for the early release of the old growth carbon? How many cycles will it take to recapture that carbon?
> Even the best of them it’s less than 6 feet of carbon containing soil.
So? Is that an average for old growth forest soil? How does it compare to new growth soil average? A single measurement is meaningless here.
More importantly, what is the comparitive density of the carbon in the soil? Depth of carbon-containing soil without a density doesn't tell me much about the total carbon stored.
> the math is clear and easy to verify.
If you say so, but unfortunately you didn't provide any math whatsoever. You seem confident though so if you have any sources, then please do share. I did a quick search for various numbers and comparisons and the numbers don't look good for your argument unless you are only comparing the rates at a given moment and ignoring the total sequestered carbon over a suitable time range (there's probably a better description for this...something like average years of sequestration for any given carbon atom during the average lifespan of an undisturbed old growth forest vs the same tract of land cyclically harvested and replanted at a profit-maximing rate over the same time period)