6 ms·

Why cant we just plant more trees? Or let the trees we have grow bigger, to soak up all that extra carbon?

by re-al 5y ago

BitwiseFool 5y ago
>"Why cant we just plant more trees?" We can, and we certainly should, but that does not solve the problem because those trees will eventually die and that carbon will cycle back through the biosphere. Mankind extracted a ton of carbon from the ground, where it was locked away, and we put it back into the air. People are trying to find ways of putting all that extra carbon back somewhere where it won't affect the cycles in nature. Trees just temporarily lock up carbon.
- nostromo 5y ago
  > those trees will eventually die and that carbon will cycle back through the biosphere. Trees in forests are self-replicating. When one dies another grows in its place. Yes, this isn't the only solution, but it's certainly part of the solution.
  - lend000 5y ago
    Yes, but the point is that there is an upper limit to the contribution, and even reforesting unrealistically vast tracts of land does not make up for carbon extracted from deeper in the crust. Growing, cutting, and burying fast growing trees deep in the Earth, then replanting them, would not have that limit (although there would be other problems keeping the land fertile).
    - nostromo 5y ago
      If you wanted to keep sequestering after the forest matures, just bulldoze the forest ever few years and put the logs in a cave. You've accomplished everything other sequestration technology promises, but you've done so in a way that is environmentally friendly.
  - otterley 5y ago
    Better than that! Trees reproduce at a ratio much higher than 1:1.
- dharma1 5y ago
  If you cut down trees (sustainable forestry with selective, not clear cutting) and use the logs in durable housing construction, furniture making etc you are taking that carbon out of the loop for a hundred+ years if the housing/furniture is well looked after. Most housing could be built with timber. It might be temporary but buys us time, and trees are amazing CO2 capture machines that are cheap to scale up - they run for free on solar energy and look after themselves. Stopping deforestation and massively boosting reforestation is one of the most effective things we can already do at scale. At this point we also need active carbon capture and significant reduction in emissions too, though - a multi-pronged approach.
- mabbo 5y ago
  Well, most of the carbon in the ground that we're burning are long-buried trees, right? I wonder what it would take to just bury a lot of trees and let them regrow naturally. This paper has some interesting ideas: https://cbmjournal.biomedcentral.com/articles/10.1186/1750-0680-3-1 https://cbmjournal.biomedcentral.com/articles/10.1186/1750-0... My approach would be to find the best CO2/$ types of trees, buy them straight from the lumber industry, and sequester them in no-longer-used quarries. Just need to figure out a scalable way to ensure anaerobic conditions to help prevent CO2 release on breakdown.
  - Voloskaya 5y ago
    You also need to find a way to speed up tree growth rate by 10x or 100x for this solution to be effective before most of the damage is done.
  - BitwiseFool 5y ago
    My understanding is that when wood first appeared on Earth nothing was able to decompose all of that cellulose for millions of years until microbes evolved a way to break the molecules apart and feed on them. I don't know if simply burying the trees is enough to sequester it away now that wood decomposes so readily.
  - mumblemumble 5y ago
    I'm no chemist, but, wild guess, you might actually make things worse by favoring decomposition into methane instead of CO2. I would think that a proper solution would require figuring out how to get all that carbon into a chemical form that is chemically stable and won't biodegrade. The ideal looks a whole lot like coal, I'd guess?
    - giantg2 5y ago
      Yep methane is multiple times more potent as a greenhouse gas.
  - fy20 5y ago
    At the time coal deposits formed the bacteria that broke down lingin and cellulose hadn't yet evolved, so just burying trees wouldn't work today as they would decay. You could probably burn the wood to produce charcoal (burning it in a low oxygen environment), and the bury that, but just cutting down a forest and burying it won't work.
- shadowlight 5y ago
  no. Unless the tree vaporizes or burns, none of it gets back into the air. It is for all intents and purposes a permanent lock up. Mankind is the gatekeeper of whether to unlock this carbon prison in our choice to burn oil or wood. Trees aren't the complete solution and the reason why has nothing to do with the tree dying and releasing the carbon. What's going on here is that plants are converting CO2 into mass. A tree that isn't growing isn't creating new mass and therefore isn't lowering carbon in the atmosphere.
  - rupert1234 5y ago
    > converting CO2 into mass CO2 has mass. It's 1 carbon atom and 2 oxygen atoms. The idea there is new mass creation going on here is absurd. Study some physics.
    - shadowlight 5y ago
      Your attitude is childish, immature and spineless. Someone like you wouldn't have the balls to say that in real life so you take it out anonymously on forums. Either way it's a technicality. I obviously meant "solid mass." CO2 must be converted to solid mass. Any person of normal brain power would've been able to figure out what I meant without delving into pointless pedantry. Go study humans and manners you lack experience with both.
      - rupert1234 5y ago
        It isn't converted into solid mass either. Study chemistry. Clueless.
        shadowlight 5y ago
        You ever heard of Carbon based life? Guess where the carbon comes from. It's 100% converted into solid mass.
- lutorm 5y ago
  Trees, unless you clearcut them (or they die off due to climate change) permanently lock up carbon. Yes, some die and decompose, but new ones grow up to take their place. It's just the total amount of biomass created that matters.
- otterley 5y ago
  Dead trees lie on the ground, with all their sequestered carbon sitting there. It's not like the carbon is going back into the atmosphere, at least not without some process like combustion. Coal is basically dead trees. Before we started extracting coal and burning it, it was harmless to the atmosphere.
  - redisman 5y ago
    They release the carbon as the decompose or burn. Sahara sounds like a very likely place for wildfires
  - r00fus 5y ago
    > It's not like the carbon is going back into the atmosphere, at least not without some process like combustion. Western USA has had a "fire season" for every year for the last like 4 years. Last year, other places like Brazil and Africa join in on the fun. So planting trees without a robust animal/insect ecosystem to decompose them before they combust is an incomplete solution.
  - m12k 5y ago
    Doesn't rotting, or being eaten by microbes or termites that eventually get eaten or die and rot eventually lead to the release of the stored carbon? AFAIK coal is composed mostly of trees that fell back before microbes evolved that could eat through their cellulose walls, and have had millennia of underground compression to further increase their stability - basically that process isn't available naturally to trees that fall today.
    - otterley 5y ago
      It takes roughly twice as long for a tree to decompose as it does to grow; and trees live a lot longer than that! So over time, the net sequestration should be positive.
- _ph_ 5y ago
  Long term the dead trees might release the carbon again to the atmosphere, but we are currently facing problems over the next decades. Even if trees would only move some amount of carbon "into the future", they could buy us precious time while we deploy other solutions for the problem. And of course, one can try to permanentely capture the carbon bound by trees by not letting them burn/rot after their life.
lsiq 5y ago
We can, how many have you planted? The problem is the space issue and that it takes a decade or two for there to be meaningful carbon uptake. Most land is private so you can't go around planting willy nilly. What's worse is that you are technically not allowed to plant on most public land either, although for small amounts of native species, you can sneak by.
- lostlogin 5y ago
  > Most land is private so you can't go around planting willy nilly. That’s pretty much how we got here, except instead of planting we mined, cut and burnt. The pathway back is rather harder.
- elevaet 5y ago
  Ahem.. Not OP, but Canadian ex-treeplanter here, and I've planted 1.2M trees. I have many friends who've planted more, a couple probably up into the 10M+ range. It seems insane that we aren't looking at trees more seriously. Here we have a self-reproducing, exponential, solar powered, organic, low-tech, carbon capture system. We don't even have to plant them, we can simply allocate land and let them do their thing on their own if we're patient for natural succession. Or we can accelerate the process by planting select species, thinning etc. We should also be setting aside more of the remaining old-growth forests to protect them from being logged, as these forests represent a standing carbon sink (aside all of the other ecological benefits of protecting old-growth forest). I know it's not the complete solution and that we need all the cards on the table, but I fear that in our appetite for high tech fixes, we're overlooking this simple biological solution.
  - jvm_ 5y ago
    Trees follow a slow-fast-slow pattern for capturing carbon. Small new trees don't capture much. Middle-aged trees capture a lot as they grow. Old-growth trees don't capture as much as they reach the end of their life-cycle. As others have said, trees are only temporary as they eventually die and need to be replanted. They're also slow to start, and need to be maintained (which costs carbon as well).
liuliu 5y ago
We release carbons from dead trees accumulated over millions of years on Earth though.
kisamoto 5y ago
Trees definitely need to be part of the solution but unfortunately global potential only revereses a decade of emissions. I wrote a short piece about it (with sources)[0] [0] https://carbonremoved.com/blog/trees-are-not-the-answer-to-climate-change/ https://carbonremoved.com/blog/trees-are-not-the-answer-to-c...
joshuawarner32 5y ago
That’s covered under ‘natural’ solutions, also eligible for the prize. All you need to do is develop a plan to scale that economically to gigaton/year capacity and claim your prize! Should be easy, right? So just do it!
- newsclues 5y ago
  Nuclear power plants for desalination plants and the build out water pipelines and rail into the Sahara desert from the ocean. Use irrigation canals covered in solar power panels for pumps etc. Plant vegetation and build up forests slowly. Slowly expand across the desert and connect both ends the block off grids and repeat irrigation and planting until the desert is gone.
breck 5y ago
Yeah this seems like the obvious thing. If everyone stopped mowing their lawns for 20 years and let trees run wild instead, would that make a dent? What about that plus turn half of our roads into parks? Anyone got a link to a good open source interactive simulator?
- sbierwagen 5y ago
  In 2016, the US burned 728 million tons of coal: https://www.ucsusa.org/resources/how-coal-works https://www.ucsusa.org/resources/how-coal-works That's one country, for one year. The world has been burning coal for more than a century. To get back to preindustrial CO2 levels, all that coal needs to be unburned and buried again. That's the scale of the problem.
cryptofistMonk 5y ago
Forests are basically carbon neutral once they're mature, peat bogs would probably be much more effective as carbon is continually sequestered underwater.
systemvoltage 5y ago
What about covering oceans in plankton?
PeterisP 5y ago
It's difficult to get enough total quantity, and it's also not rapid enough as it takes decades after planting (which would also take a lot of time) to soak up that extra carbon. One aspect is that the required land area - https://climate.nasa.gov/news/2927/examining-the-viability-of-planting-trees-to-help-mitigate-climate-change/ https://climate.nasa.gov/news/2927/examining-the-viability-o... mentions 900 million hectares (2.2 billion acres), which would roughly cover the 10Gt/year asked by the x-prize - is enormous, and it's not an accident or negligence that this land isn't forested now, it's generally because we turned it into farmland or pastures. Are we willing to take away 900 million hectares of land that produces food for the world and money for the locals away from that productive use and turn all of it into unproductive forest that won't get used for logging? Perhaps we are, but if there are other options for carbon removal that don't require as much land resources, that would be preferable.
Tiktaalik 5y ago
Where? And what makes you think this isn't already happening? I mean, in Canada when they raze a patch of forest they already immediately replant it. The areas that aren't forested are so because they're being used for agriculture.

Why cant we just plant more trees? Or let the trees we have grow bigger, to soak up all that extra carbon?

by re-al 5y ago

Why cant we just plant more trees? Or let the trees we have grow bigger, to soak up all that extra carbon?

>"Why cant we just plant more trees?" We can, and we certainly should, but that does not solve the problem because those trees will eventually die and that carbon will cycle back through the biosphere. Mankind extracted a ton of carbon from the ground, where it was locked away, and we put it back into the air. People are trying to find ways of putting all that extra carbon back somewhere where it won't affect the cycles in nature. Trees just temporarily lock up carbon.

nostromo 5y ago
> those trees will eventually die and that carbon will cycle back through the biosphere. Trees in forests are self-replicating. When one dies another grows in its place. Yes, this isn't the only solution, but it's certainly part of the solution.
- lend000 5y ago
  Yes, but the point is that there is an upper limit to the contribution, and even reforesting unrealistically vast tracts of land does not make up for carbon extracted from deeper in the crust. Growing, cutting, and burying fast growing trees deep in the Earth, then replanting them, would not have that limit (although there would be other problems keeping the land fertile).
  - nostromo 5y ago
    If you wanted to keep sequestering after the forest matures, just bulldoze the forest ever few years and put the logs in a cave. You've accomplished everything other sequestration technology promises, but you've done so in a way that is environmentally friendly.
- otterley 5y ago
  Better than that! Trees reproduce at a ratio much higher than 1:1.
dharma1 5y ago
If you cut down trees (sustainable forestry with selective, not clear cutting) and use the logs in durable housing construction, furniture making etc you are taking that carbon out of the loop for a hundred+ years if the housing/furniture is well looked after. Most housing could be built with timber. It might be temporary but buys us time, and trees are amazing CO2 capture machines that are cheap to scale up - they run for free on solar energy and look after themselves. Stopping deforestation and massively boosting reforestation is one of the most effective things we can already do at scale. At this point we also need active carbon capture and significant reduction in emissions too, though - a multi-pronged approach.
mabbo 5y ago
Well, most of the carbon in the ground that we're burning are long-buried trees, right? I wonder what it would take to just bury a lot of trees and let them regrow naturally. This paper has some interesting ideas: https://cbmjournal.biomedcentral.com/articles/10.1186/1750-0680-3-1 https://cbmjournal.biomedcentral.com/articles/10.1186/1750-0... My approach would be to find the best CO2/$ types of trees, buy them straight from the lumber industry, and sequester them in no-longer-used quarries. Just need to figure out a scalable way to ensure anaerobic conditions to help prevent CO2 release on breakdown.
- Voloskaya 5y ago
  You also need to find a way to speed up tree growth rate by 10x or 100x for this solution to be effective before most of the damage is done.
- BitwiseFool 5y ago
  My understanding is that when wood first appeared on Earth nothing was able to decompose all of that cellulose for millions of years until microbes evolved a way to break the molecules apart and feed on them. I don't know if simply burying the trees is enough to sequester it away now that wood decomposes so readily.
- mumblemumble 5y ago
  I'm no chemist, but, wild guess, you might actually make things worse by favoring decomposition into methane instead of CO2. I would think that a proper solution would require figuring out how to get all that carbon into a chemical form that is chemically stable and won't biodegrade. The ideal looks a whole lot like coal, I'd guess?
  - giantg2 5y ago
    Yep methane is multiple times more potent as a greenhouse gas.
- fy20 5y ago
  At the time coal deposits formed the bacteria that broke down lingin and cellulose hadn't yet evolved, so just burying trees wouldn't work today as they would decay. You could probably burn the wood to produce charcoal (burning it in a low oxygen environment), and the bury that, but just cutting down a forest and burying it won't work.
shadowlight 5y ago
no. Unless the tree vaporizes or burns, none of it gets back into the air. It is for all intents and purposes a permanent lock up. Mankind is the gatekeeper of whether to unlock this carbon prison in our choice to burn oil or wood. Trees aren't the complete solution and the reason why has nothing to do with the tree dying and releasing the carbon. What's going on here is that plants are converting CO2 into mass. A tree that isn't growing isn't creating new mass and therefore isn't lowering carbon in the atmosphere.
- rupert1234 5y ago
  > converting CO2 into mass CO2 has mass. It's 1 carbon atom and 2 oxygen atoms. The idea there is new mass creation going on here is absurd. Study some physics.
  - shadowlight 5y ago
    Your attitude is childish, immature and spineless. Someone like you wouldn't have the balls to say that in real life so you take it out anonymously on forums. Either way it's a technicality. I obviously meant "solid mass." CO2 must be converted to solid mass. Any person of normal brain power would've been able to figure out what I meant without delving into pointless pedantry. Go study humans and manners you lack experience with both.
    - rupert1234 5y ago
      It isn't converted into solid mass either. Study chemistry. Clueless.
      - shadowlight 5y ago
        You ever heard of Carbon based life? Guess where the carbon comes from. It's 100% converted into solid mass.
lutorm 5y ago
Trees, unless you clearcut them (or they die off due to climate change) permanently lock up carbon. Yes, some die and decompose, but new ones grow up to take their place. It's just the total amount of biomass created that matters.
otterley 5y ago
Dead trees lie on the ground, with all their sequestered carbon sitting there. It's not like the carbon is going back into the atmosphere, at least not without some process like combustion. Coal is basically dead trees. Before we started extracting coal and burning it, it was harmless to the atmosphere.
- redisman 5y ago
  They release the carbon as the decompose or burn. Sahara sounds like a very likely place for wildfires
- r00fus 5y ago
  > It's not like the carbon is going back into the atmosphere, at least not without some process like combustion. Western USA has had a "fire season" for every year for the last like 4 years. Last year, other places like Brazil and Africa join in on the fun. So planting trees without a robust animal/insect ecosystem to decompose them before they combust is an incomplete solution.
- m12k 5y ago
  Doesn't rotting, or being eaten by microbes or termites that eventually get eaten or die and rot eventually lead to the release of the stored carbon? AFAIK coal is composed mostly of trees that fell back before microbes evolved that could eat through their cellulose walls, and have had millennia of underground compression to further increase their stability - basically that process isn't available naturally to trees that fall today.
  - otterley 5y ago
    It takes roughly twice as long for a tree to decompose as it does to grow; and trees live a lot longer than that! So over time, the net sequestration should be positive.
_ph_ 5y ago
Long term the dead trees might release the carbon again to the atmosphere, but we are currently facing problems over the next decades. Even if trees would only move some amount of carbon "into the future", they could buy us precious time while we deploy other solutions for the problem. And of course, one can try to permanentely capture the carbon bound by trees by not letting them burn/rot after their life.

lsiq 5y ago

We can, how many have you planted? The problem is the space issue and that it takes a decade or two for there to be meaningful carbon uptake. Most land is private so you can't go around planting willy nilly. What's worse is that you are technically not allowed to plant on most public land either, although for small amounts of native species, you can sneak by.

lostlogin 5y ago
> Most land is private so you can't go around planting willy nilly. That’s pretty much how we got here, except instead of planting we mined, cut and burnt. The pathway back is rather harder.
elevaet 5y ago
Ahem.. Not OP, but Canadian ex-treeplanter here, and I've planted 1.2M trees. I have many friends who've planted more, a couple probably up into the 10M+ range. It seems insane that we aren't looking at trees more seriously. Here we have a self-reproducing, exponential, solar powered, organic, low-tech, carbon capture system. We don't even have to plant them, we can simply allocate land and let them do their thing on their own if we're patient for natural succession. Or we can accelerate the process by planting select species, thinning etc. We should also be setting aside more of the remaining old-growth forests to protect them from being logged, as these forests represent a standing carbon sink (aside all of the other ecological benefits of protecting old-growth forest). I know it's not the complete solution and that we need all the cards on the table, but I fear that in our appetite for high tech fixes, we're overlooking this simple biological solution.
- jvm_ 5y ago
  Trees follow a slow-fast-slow pattern for capturing carbon. Small new trees don't capture much. Middle-aged trees capture a lot as they grow. Old-growth trees don't capture as much as they reach the end of their life-cycle. As others have said, trees are only temporary as they eventually die and need to be replanted. They're also slow to start, and need to be maintained (which costs carbon as well).

liuliu 5y ago

We release carbons from dead trees accumulated over millions of years on Earth though.

kisamoto 5y ago

Trees definitely need to be part of the solution but unfortunately global potential only revereses a decade of emissions. I wrote a short piece about it (with sources)[0] [0] https://carbonremoved.com/blog/trees-are-not-the-answer-to-climate-change/ https://carbonremoved.com/blog/trees-are-not-the-answer-to-c...

joshuawarner32 5y ago

That’s covered under ‘natural’ solutions, also eligible for the prize. All you need to do is develop a plan to scale that economically to gigaton/year capacity and claim your prize! Should be easy, right? So just do it!

newsclues 5y ago
Nuclear power plants for desalination plants and the build out water pipelines and rail into the Sahara desert from the ocean. Use irrigation canals covered in solar power panels for pumps etc. Plant vegetation and build up forests slowly. Slowly expand across the desert and connect both ends the block off grids and repeat irrigation and planting until the desert is gone.

breck 5y ago

Yeah this seems like the obvious thing. If everyone stopped mowing their lawns for 20 years and let trees run wild instead, would that make a dent? What about that plus turn half of our roads into parks? Anyone got a link to a good open source interactive simulator?

sbierwagen 5y ago
In 2016, the US burned 728 million tons of coal: https://www.ucsusa.org/resources/how-coal-works https://www.ucsusa.org/resources/how-coal-works That's one country, for one year. The world has been burning coal for more than a century. To get back to preindustrial CO2 levels, all that coal needs to be unburned and buried again. That's the scale of the problem.

cryptofistMonk 5y ago

Forests are basically carbon neutral once they're mature, peat bogs would probably be much more effective as carbon is continually sequestered underwater.

systemvoltage 5y ago

What about covering oceans in plankton?

PeterisP 5y ago

It's difficult to get enough total quantity, and it's also not rapid enough as it takes decades after planting (which would also take a lot of time) to soak up that extra carbon. One aspect is that the required land area - https://climate.nasa.gov/news/2927/examining-the-viability-of-planting-trees-to-help-mitigate-climate-change/ https://climate.nasa.gov/news/2927/examining-the-viability-o... mentions 900 million hectares (2.2 billion acres), which would roughly cover the 10Gt/year asked by the x-prize - is enormous, and it's not an accident or negligence that this land isn't forested now, it's generally because we turned it into farmland or pastures. Are we willing to take away 900 million hectares of land that produces food for the world and money for the locals away from that productive use and turn all of it into unproductive forest that won't get used for logging? Perhaps we are, but if there are other options for carbon removal that don't require as much land resources, that would be preferable.

Tiktaalik 5y ago

Where? And what makes you think this isn't already happening? I mean, in Canada when they raze a patch of forest they already immediately replant it. The areas that aren't forested are so because they're being used for agriculture.