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Not to discourage you, but mature forest is generally close to carbon neutral. It stores a reasonable amount of carbon, but usually isn't sequestering much mor

by nkurz 3y ago

Not to discourage you, but mature forest is generally close to carbon neutral. It stores a reasonable amount of carbon, but usually isn't sequestering much more. For actually offsetting carbon, what you want is new growth. Typically, this is done by cutting the trees to make room for new ones while preventing the wood you cut from decomposing back into CO2. So if your goal is direct carbon offset, your best bet might cut a clearing and use it to build your house --- possibly even intentionally cutting a larger clearing than you otherwise would. Unless your land was cut recently, in which case letting it grow the way you plan might be just fine. If your new land is in the Northeastern US, you might enjoy reading the reports from this group: https://wildlandsandwoodlands.org/vision/overview/ https://wildlandsandwoodlands.org/vision/overview/

pvaldes 3y ago
People repeat this mantra a lot. The whole reasoning behind the idea is wrong
- voisin 3y ago
  Conclusions are almost invariably stronger when presented alongside evidence or even supporting arguments.
  - ProllyInfamous 3y ago
    The evidence I will present (about the aforementioned land) is this: Two separate creeks are on either sides of the property, and I've already seen so much life blossoming! ...of course, this is only anecdotal.
  - pvaldes 3y ago
    The idea is based in the hypothesis that old trees grow slower, because the general universal rule that mature species spend resources on sexual reproduction, so they have less resources to grow This is just a general rule, but the real life has a few caveats. 1) Grow is complex. The first problem is that we don't really know "how much" slower is "slower". Has not being studied for most species, because finding a 500 year old ash that is not pruned or coppiced is basically impossible [1]. And we need to remind that trees are clonal organisms arranged around a very few parts that repeat themselves. Even if old trees would really grow much slower than saplings, they have a huge, huge difference on the --number of growing points--. This should overcome any speed difference. The result is that older trees still add mass on a velocity that young trees can't. Other problem is that identifying grow with "how taller respect to the last year" is not practical. Biomass is the correct term in ecology. Young trees grow abnormally fast because they are searching for light. And this fast grow is the thinnest possible that can support the tree and still put it over its competitors. It can't be sustained later without risking for the tree integrity. This grow shouldn't be promoted. Wider is what we want. A tree is not growing slow just because is only 1cm taller than the last year. Mature trees have a "deploying umbrella" phase. 2) In the real life, trees often don't grow a lot the first years. Most of the big oaks (and I had cultured a few) show a frozen grow in the first two years. They use it first year to make a deep root and 2 (two!) small leaves. Period. In the second year maybe four to eight leaves if the area is very favourable. The whole oak weights... dunno, maybe 50 grams? at this period. The CO2 captured from the air is close to zero and even could be a negative value while the sapling feeds on its acorn. Then at the fourth year there is a phase of (maybe) fast grow for a couple decades, but only if there aren't herbivores around and only if the area does not receive light. In the same time, older trees would have included tens or thousands kilograms in each one of its main branches and the same for their main roots. Plus the soil generated. Plus the fruits. And we can save the best for the last. Mature trees produce pollen. This is an output in our supposedly Carbon neutral system. The number of people that had quantified seriously how much pollen produces a tree could fit maybe in a small room, but I'll assume that a fair sized tree produces tens of Kg of pollen each flowering season. What we know is that one single conifer can "paint" a car with pollen in no time, and can do it for weeks. This pollen is protected and enclosed in a hard cage of Sporepollenin. Sporepollenin is simply one of the most durable organic substances known by us. This structure is able to trap C for hundreds of millions of years in favourable conditions. Hundreds of millions!. Is --exactly-- the stuff what we crave for, and that we are looking for like crazy. Except because some people can't avoid the itch to burn the soil. Though luck. [1] When you coppice a tree, you modify the speed of regrow. My bet is that when on panic mode, old trees could easily have bursts of superfast grow. Easily much faster than a sapling. This mechanism is behind the recent fever (ehum, scam) of planting kiri trees.
- nkurz 3y ago
  I know from your other comments that you are knowledgeable in these areas, so perhaps you could explain further? I could be wrong, or as I think might be the case, the situation might be different in different ecosystems. The Northeastern US has more forest cover today than it's had since immediately after it was settled by Europeans 300-plus years ago. We should stringently preserve the tiny remnants of old growth that remain, but we've got a lot of 50-150 year old regrowth to work with. While preserving it from development should be a goal, it's not clear that leaving it untouched is the best strategy. To focus the discussion, here's a very recent report by the group I linked above: https://wildlandsandwoodlands.org/news-and-stories/new-england-study-calls-for-dramatic-increase-in-sustainable-forestry/ https://wildlandsandwoodlands.org/news-and-stories/new-engla.... I just submitted it here: https://news.ycombinator.com/item?id=39880257 https://news.ycombinator.com/item?id=39880257. I'd be interested to read your criticism of it.
ProllyInfamous 3y ago
>Unless your land was cut recently About a third of it was clearcut last in the mid-80's, to grow hay... so those trees are "new" on the timelines of trees. The other part was entirely clearcut during the civil war, and then again early 20th century (in places) for coal extraction. >mature forest is generally close to carbon neutral. Even the 19th century portions are filled with all manner of life / transpiration.
- nkurz 3y ago
  >> mature forest is generally close to carbon neutral. > Even the 19th century portions are filled with all manner of life / transpiration. Definitely. We own and live on a somewhat similar parcel in Vermont next to the Green Mountain National Forest. I'm actually not saying that you should cut these areas, only that that you should consider doing so if your primary goal truly is carbon offsets. Although I think offsetting carbon is a good thing if all else was equal, it's not the thing I would prioritize here. You are a drop in the bucket next to all the adjoining land. Think of what you can do differently to provide for niches that are not already provided. My personal emphasis is focused more on wildlife habitat than carbon.
gregwebs 3y ago
This research states that old growth forests continue to sink carbon and as I understand it actually sink more carbon than new growth: https://www.nature.com/articles/nature12914 https://www.nature.com/articles/nature12914 It's not what I had expected. Maybe there's a problem with the research, but I think everyone just assumed that new growth was better without studying the issue carefully.
- Retric 3y ago
  That study is about individual trees not a mature forest. “nature of productivity at the scale of the individual tree” As the average tree in a forest keeps getting older you keep sequestering carbon and older trees are sequestering faster than young ones. The issue is eventually you reach an equilibrium point where the average age becomes a constant because trees have a finite lifespan. Globally most forests were cut down relatively decently so they haven’t reached equilibrium. But when you start talking the next 100+ years it does become an issue.
- nkurz 3y ago
  Thanks, I'll try to check it out. Full article here: https://sci-hub.se/https://doi.org/10.1038/nature12914 https://sci-hub.se/https://doi.org/10.1038/nature12914 At a quick skim, I'm not sure this contradicts what I'm saying. Yes, large trees that are getting larger are excellent carbon sinks. On the other hand, there aren't many such large trees, and they tend to outcompete other growth. From the article: Second, our findings are similarly compatible with the well-known age-related decline in productivity at the scale of even-aged forest stands. ... We highlight the fact that increasing individual tree growth rate does not automatically result in increasing stand productivity because tree mortality can drive orders-of-magnitude reductions in population density. That is, even though the large trees in older, even-aged stands may be growing more rapidly, such stands have fewer trees. Tree population dynamics, especially mortality, can thus be a significant contributor to declining productivity at the scale of the forest stand. My point is contained within "the well-known age-related decline in productivity at the scale of even-aged forest stands" that they refer to. That said, I agree that this point is not universally true and depends on a lot of local factors.

by nkurz 3y ago

pvaldes 3y ago

People repeat this mantra a lot. The whole reasoning behind the idea is wrong

voisin 3y ago
Conclusions are almost invariably stronger when presented alongside evidence or even supporting arguments.
- ProllyInfamous 3y ago
  The evidence I will present (about the aforementioned land) is this: Two separate creeks are on either sides of the property, and I've already seen so much life blossoming! ...of course, this is only anecdotal.
- pvaldes 3y ago
  The idea is based in the hypothesis that old trees grow slower, because the general universal rule that mature species spend resources on sexual reproduction, so they have less resources to grow This is just a general rule, but the real life has a few caveats. 1) Grow is complex. The first problem is that we don't really know "how much" slower is "slower". Has not being studied for most species, because finding a 500 year old ash that is not pruned or coppiced is basically impossible [1]. And we need to remind that trees are clonal organisms arranged around a very few parts that repeat themselves. Even if old trees would really grow much slower than saplings, they have a huge, huge difference on the --number of growing points--. This should overcome any speed difference. The result is that older trees still add mass on a velocity that young trees can't. Other problem is that identifying grow with "how taller respect to the last year" is not practical. Biomass is the correct term in ecology. Young trees grow abnormally fast because they are searching for light. And this fast grow is the thinnest possible that can support the tree and still put it over its competitors. It can't be sustained later without risking for the tree integrity. This grow shouldn't be promoted. Wider is what we want. A tree is not growing slow just because is only 1cm taller than the last year. Mature trees have a "deploying umbrella" phase. 2) In the real life, trees often don't grow a lot the first years. Most of the big oaks (and I had cultured a few) show a frozen grow in the first two years. They use it first year to make a deep root and 2 (two!) small leaves. Period. In the second year maybe four to eight leaves if the area is very favourable. The whole oak weights... dunno, maybe 50 grams? at this period. The CO2 captured from the air is close to zero and even could be a negative value while the sapling feeds on its acorn. Then at the fourth year there is a phase of (maybe) fast grow for a couple decades, but only if there aren't herbivores around and only if the area does not receive light. In the same time, older trees would have included tens or thousands kilograms in each one of its main branches and the same for their main roots. Plus the soil generated. Plus the fruits. And we can save the best for the last. Mature trees produce pollen. This is an output in our supposedly Carbon neutral system. The number of people that had quantified seriously how much pollen produces a tree could fit maybe in a small room, but I'll assume that a fair sized tree produces tens of Kg of pollen each flowering season. What we know is that one single conifer can "paint" a car with pollen in no time, and can do it for weeks. This pollen is protected and enclosed in a hard cage of Sporepollenin. Sporepollenin is simply one of the most durable organic substances known by us. This structure is able to trap C for hundreds of millions of years in favourable conditions. Hundreds of millions!. Is --exactly-- the stuff what we crave for, and that we are looking for like crazy. Except because some people can't avoid the itch to burn the soil. Though luck. [1] When you coppice a tree, you modify the speed of regrow. My bet is that when on panic mode, old trees could easily have bursts of superfast grow. Easily much faster than a sapling. This mechanism is behind the recent fever (ehum, scam) of planting kiri trees.
nkurz 3y ago
I know from your other comments that you are knowledgeable in these areas, so perhaps you could explain further? I could be wrong, or as I think might be the case, the situation might be different in different ecosystems. The Northeastern US has more forest cover today than it's had since immediately after it was settled by Europeans 300-plus years ago. We should stringently preserve the tiny remnants of old growth that remain, but we've got a lot of 50-150 year old regrowth to work with. While preserving it from development should be a goal, it's not clear that leaving it untouched is the best strategy. To focus the discussion, here's a very recent report by the group I linked above: https://wildlandsandwoodlands.org/news-and-stories/new-england-study-calls-for-dramatic-increase-in-sustainable-forestry/ https://wildlandsandwoodlands.org/news-and-stories/new-engla.... I just submitted it here: https://news.ycombinator.com/item?id=39880257 https://news.ycombinator.com/item?id=39880257. I'd be interested to read your criticism of it.

ProllyInfamous 3y ago

>Unless your land was cut recently About a third of it was clearcut last in the mid-80's, to grow hay... so those trees are "new" on the timelines of trees. The other part was entirely clearcut during the civil war, and then again early 20th century (in places) for coal extraction. >mature forest is generally close to carbon neutral. Even the 19th century portions are filled with all manner of life / transpiration.

nkurz 3y ago
>> mature forest is generally close to carbon neutral. > Even the 19th century portions are filled with all manner of life / transpiration. Definitely. We own and live on a somewhat similar parcel in Vermont next to the Green Mountain National Forest. I'm actually not saying that you should cut these areas, only that that you should consider doing so if your primary goal truly is carbon offsets. Although I think offsetting carbon is a good thing if all else was equal, it's not the thing I would prioritize here. You are a drop in the bucket next to all the adjoining land. Think of what you can do differently to provide for niches that are not already provided. My personal emphasis is focused more on wildlife habitat than carbon.

gregwebs 3y ago

This research states that old growth forests continue to sink carbon and as I understand it actually sink more carbon than new growth: https://www.nature.com/articles/nature12914 https://www.nature.com/articles/nature12914 It's not what I had expected. Maybe there's a problem with the research, but I think everyone just assumed that new growth was better without studying the issue carefully.

Retric 3y ago
That study is about individual trees not a mature forest. “nature of productivity at the scale of the individual tree” As the average tree in a forest keeps getting older you keep sequestering carbon and older trees are sequestering faster than young ones. The issue is eventually you reach an equilibrium point where the average age becomes a constant because trees have a finite lifespan. Globally most forests were cut down relatively decently so they haven’t reached equilibrium. But when you start talking the next 100+ years it does become an issue.
nkurz 3y ago
Thanks, I'll try to check it out. Full article here: https://sci-hub.se/https://doi.org/10.1038/nature12914 https://sci-hub.se/https://doi.org/10.1038/nature12914 At a quick skim, I'm not sure this contradicts what I'm saying. Yes, large trees that are getting larger are excellent carbon sinks. On the other hand, there aren't many such large trees, and they tend to outcompete other growth. From the article: Second, our findings are similarly compatible with the well-known age-related decline in productivity at the scale of even-aged forest stands. ... We highlight the fact that increasing individual tree growth rate does not automatically result in increasing stand productivity because tree mortality can drive orders-of-magnitude reductions in population density. That is, even though the large trees in older, even-aged stands may be growing more rapidly, such stands have fewer trees. Tree population dynamics, especially mortality, can thus be a significant contributor to declining productivity at the scale of the forest stand. My point is contained within "the well-known age-related decline in productivity at the scale of even-aged forest stands" that they refer to. That said, I agree that this point is not universally true and depends on a lot of local factors.