I did a rough spreadsheet some time back based on this 1998 EPA carbon sequestration worksheet [1] and found that an average person from a high carbon output country needs about 600-1000 trees to offset their carbon output.
There are about 3 trillion trees for a population of 7 billion people for an average of 428 trees per person, so that means you have to make up the delta of about 172 to 572 trees over the course of your lifetime to erase your carbon footprint (of course, young trees don't sequester as much carbon, so your footprint will still be positive for much of your lifetime - but as the trees get older, they sequester at a higher rate per year, which eventually gives you a negative footprint). This projection was based on the CO2 sequestration per year and the average survival rate documented in [1].
No easy way to plot this - planting trees to sequester CO2 may or may not have a net positive impact at scale for a variety of reasons:
1) The timescale is very long - a single tree to drive carbon neutrality is MOST optimistically pegged at 40 - 100 years depending on species. With expanding populations planning or guaranteeing execution on that time scale is limited. AKA it's very unlikely that most efforts, unless planted in an evergreen protected land will actually drive a net positive impact.
2) Forest soil and topsoil (from dropped branches, leaves, etc) can sequester up to 2x as much carbon as the actual trees themselves and is typically counted in the "net negative" C02 impact. But warming temperatures creates a negative feedback loop increases the rate of C02 release from soil.
3) Governments, in their effort to drive commercial tree planting, are accidentally driving the wrong incentives - farmed forests are <50% as effective at C02 sequester as natural forests and the act of burning wood pellets for fuel and or even using for building materials dramatically reduces and in fact calls into question ANY C02 benefits.
Effectively the only sure fire way towards atmospheric CO2 reduction is cutting consumption
Electricity from solar photovoltaic generation has life cycle emissions 90-95% lower than fossil-derived electricity, per median figures in the IPCC's 2014 tabulation of global warming potential of selected electricity sources. Geothermal, concentrated solar power, nuclear power, and wind power have even lower life cycle emissions.
Displacing fossil-derived electricity with enough low-carbon electricity to supply an air conditioner is more effective than raising the AC temperature one degree or planting a tree.
The key issue is to reduce emissions. Sometimes that necessitates reduced consumption of energy services [1]. But reducing consumption is not sufficient and often not necessary to deeply cut emissions.
If 3 tons of CO2 per capita per year is a sustainable emissions rate, then the US emits at about 550% of the sustainable rate. Even Cuba emits at 107% of the sustainable rate. No polity is going to voluntarily reduce their material standard of living below that of Cuba. And even a super-emitter like the US could reach the sustainable rate with a combination of more efficient energy use and non-fossil (renewable and nuclear) primary energy production substituting for fossils. So I think that "stop burning fossils for air conditioning" is a prescription closer to solving the root problem than "endure a little more discomfort in the air conditioning season."
[1] For example, there is no foreseeable technology that will enable trans-Atlantic passenger flights without burning chemical fuels. Long distance flights could burn synthetic fuels made using non-fossil electricity, but that would raise fuel prices. Whether by fiat or by pricing, long distance air travel will necessarily become less common if/when aviation faces pressure to reduce CO2 emissions.
I 100% agree. I originally started banging out a comment saying forget the trees, build more nuclear power but didn't want to invite a downvoting brigade, which I effectively walked into anyways :)
Introducing nuclear power in climate discussions tends to cause flamewars because it's often introduced by someone making extreme blanket statements, like "humans cannot be trusted with nuclear power" or "nuclear is the only available solution to climate change."
Just mention it as one of the low-emissions alternatives to fossil power. Cite climate-focused organizations for support rather than industry-specific organizations. The aim is to reduce emissions, not to promote one specific technology toward that end.
I wish that we just had carbon tax-and-dividend instead of a thousand different regulations and tax code incentives mandating or nudging toward specific kinds of efficiency measures and fossil replacements. At the same time I understand that carbon taxes face enormous popular opposition while tax credits and CAFE standards don't, so I'll accept having 3 different kinds of federal tax incentives to separately promote nuclear power, wind power, and solar power (plus a myriad of differently structured state level incentives) as the best the US can currently do.
The problem with Nuclear is it needs huge subsides to be cost competitive with battery backed Wind / Solar or Hydro, even more if you want it to load follow. With just a carbon tax and no specific Nuclear subsidies, Nuclear is rarely a good option.
In theory it seems like a great idea, in practice with decades of 10’s to 100’s of Billions in R&D it’s unlikely to improve that much within the next 5-10 years. (106 Billion and counting from the US government alone: https://www.forbes.com/sites/jeffmcmahon/2018/07/09/nuclear-...)
I agree that new nuclear power doesn't appear to be competitive with new renewables in the near term. It might be competitive again as renewable penetration gets high and storage costs rise. If there were just one tax incentive scheme, aimed at reducing CO2 emissions, we could be sure that tax incentives were optimizing for low emissions without distorting the market in favor of overly specific technology choices. But as I mentioned before, I'll take the overly specific and distortionary incentives if the alternative is "no incentives at all for reducing emissions."
It's probably needed in northern countries for COMPLETE decarbonization. And basically all large infrastructure has some level of subsidy, definitely including wind, solar, and hydro.
Lithium-air is one technology that would easily enable transatlantic flights. Even lithium-sulfur/metal/etc (which are much nearer term and can be had in small batches now if you call around) you could get you transatlantic (Canada to Ireland) with a very efficient airframe and even with lithium-ion with a very efficient airframe if you hop over Canada, Greenland, and Iceland.
How is using wood as a building material bad? I would think that putting carbon into our walls and patios would be as good a place as any to keep it out of the atmosphere?
We should also look to compare hempcrete or similar lightweight materials with superior insulation qualities; "an un-rendered 30 cm thick hemp concrete wall enables a storage of 36.08 kg of CO2 per m2 [1]."
If we can get all those steps onto electric power instead of internal combustion, then (assuming the power's coming from renewables, hydroelectric, or nuclear) that should eliminate the issue, right?
I agree completely. I live in a century home. The spruce lumber in my walls is safe and dry and has been there decades longer than it would have been if those trees had been left to die and rot on their own.
Farmed forest can be very effective in the short term for CO2 sequestration how ever, although the net CO2 sequestration over 200 years or so may be lower the sequestration in the short term can be very high. This gives you time to reduce the amount of emissions that are being made in the first place. Planting trees is not a long term solution in and off itself but it is an important tool in reducing emissions
I would say in 40 years we’re going to be in a much much worse situation so is your argument don’t bother ? Else we should do both, plant a trillion trees and replace fossil fuels and civilisation might be ok?
Sorry but it just seems like you’re trying to make this a negative idea, when it’s a clearly positive thing outside of just sequestering carbon, there are other areas of the eco system improved by having more trees.
If you look at his further posts, his positions are fabricated worst case scenario. For example he suggests that there is no point in planting trees because you're going to drive there in your SUV and then come home and run your AC. This might be true for some people, but it's not for me as my house doesn't have AC and I don't own an SUV. I car pool or drive a prius to plant trees. Also we're not planting trees in places that are then harvested.
When I see people who are anti-tree planting, I wonder if there is some authoritarian predilections at play and anything that doesn't result in central control or provide some mechanism for rent seeking or corruption is going to get down played.
The reality is that if you go and work with your local land management folks who can give you guidance on the types of trees and where to plant them, then going out and spending a weekend putting fifty trees in the ground, will give you quite a nice reduction for the CO2 emissions necessary to plant them. What's more is trees reproduce on their own. If you get a tree into the ground it will likely produce two additional trees over its lifetime if not more.
Where do you go to plant trees such that you can be certain the trees won't just be cut down in a few years, and also don't simply displace other trees that would otherwise grow?
Also, do you keep track of the trees to make sure they actually grow? Just planting the seed or even a sapling is far from sufficient to ensure that carbon sequestration occurs. Young trees are food for a variety of animals and insects. Do you know what fraction of the trees you plant actually reach maturity? I've seen estimates that far fewer than one in five do.
So... no where? Where I live you either live in an apartment or in a house that is 5 feet away from neighboring houses in all directions. What percentage of the population is rich enough to own empty land that they can plants trees on?
Maybe sounds too much like spouting from the climate change denier camp?
Which I am the opposite of.
There are a lot of flower & daisy soft solutions to C02.
Drive to the suburban forest in your SUV, plant 100 trees that will inevitably be cut down long before they have a carbon negative impact, come home and run your AC.
You're still running 1000/1 in negative C02 balance.
Vs finds ways to dramatically cut use, double down on investigative hard solutions like nuclear and major infrastructure projects like mass transport, car banning, new taxation on major freight (sea and road) to force efficiency adoption etc.
Lots of hard solutions are readily available to solving the problem, but by definition they're hard.
We've gotta get past the argument pattern of "don't reduce consumption; sequester!" and "don't sequester; reduce consumption!" A lot of both are needed.
I agree with the point that planting 100 trees should not leave anyone feeling they've done their part. Repeating the math until we're blue in the face is what helps there I guess.
But convincing the entire population of the world to set their thermostat 1 degree higher during the summer months would have a 1000x multiple impact on a 40x shorter time scale than if every one of those people planted a tree.
The spirit of my comment is that in general people LOVE the path of least resistance.
Ask the average person about combatting climate change and their response is "plant more trees".
Because that's easy, shit you can pay the gardener to do it or donate $10 to a plant the tree collective and feel instant gratification with no sacrifice.
Vs the highest possible impact solution which is cutting personal consumption - even a little bit!
You can easily plant 1000 trees to cover some of the people who won't bother, but setting your thermostat 1000 degrees higher in the summer won't do anything more.
This is all well and good, except that you cannot easily plant 1000 trees and ensure they continue to exist in mature form forever. At least, you cannot for most values of "you." Maintaining 1000 mature trees is not a trivial matter.
I wonder about this too - all these charities for planting trees or renting carbon scrubbers or buying carbon offsets, they all have a certain level of capacity after which they'd be sold out. So buying carbon offsets don't really offset all your carbon.
> But convincing the entire population of the world to set their thermostat 1 degree higher
This confused me for longer than I'd care to admit, but now that I get it, I'd just say that a much smaller proportion of 'the entire population of the world' - even the developed world - has AC than it might seem to an American perspective.
Trees can keep running for 40-100 years using your figures. Governments can compulsory purchase and designate regions as wilderness or reserve, and require region appropriate planting. Perhaps to resemble former natural forest.
You can't ask people to set their thermostat 1 degree warmer every year for that 40-100 years. You can expect there to be scope for continued tree planting for decades.
Neither is a sole solution, but both are part of a holistic, reasoned and coordinated journey to carbon neutrality.
"Drive to the suburban forest in your SUV, plant 100 trees that will inevitably be cut down long before they have a carbon negative impact, come home and run your AC. You're still running 1000/1 in negative C02 balance."
So do 1000 times that, and don't plant them in a suburban forest but one that will stay around longer. Or contribute money to tree planting initiatives who do it right.
Each apple, each year, for the last 40 years, that somebody grow in their garden, is an apple less that must be moved burning gasoline from Idaho or Colorado to a market near you, one piece of fruit less that must be waxed and wrapped in plastic and put in one-use wood boxes, before to be moved again to your house, probably burning a litte more gaz.
I didn't downvote, but I suspect those counterpoints are second-order and very minor compared to the sequestration rates of a tree itself. I can't bring myself to believe that because of those counterpoints, every new tree on average sequesters zero carbon. The important stat is on average, how much carbon does each new tree sequester; that's what drives the models.
I'm pretty confident OP up there also loves trees. But we're at a point where we need to calculate efforts and allocate resources wisely. Maybe we need fewer forests and more nuclear. idk.
I know for a fact every tree I can plant with my bare hands would be carbon negative, because I did the math.
I recall there being some considerable surprise when they figured out that trees gain mass (of which a fraction is carbon) faster as they get older.
It's not that shocking. If two tree rings are the same width, the outer one contains more material due to the larger circumference. The surface area of a tree increases every year until it starts to decline. In a healthy tree, canopy and roots are balanced, and any gain or loss in material above ground is mirrored below. Dead roots rejoin the food chain much, much slower than twigs and leaves, so nearly half the carbon that goes into the tree goes into the ground and stays there, even if you cut the tree for timber. And due to root fusion, some of the roots may survive... if you didn't cut down all of the trees of the same species. I'm looking at you, timber industry.
There is one thing that I don't understand. I plant 1000 trees, I sequester the CO2 I create by driving, heating my home and all the activities done by third parties to keep me alive (food, hospitals, etc). But that CO2 is still under the sky and most of it will be released when the trees die. It's not like we're pumping it back into oil fields or coal mines and never see it again. So this 1T trees initiative is a stop gap measure to buy us some time but it won't solve the problem. But it's better than doing nothing.
If a tree is planted, grows, and then for example is burned down and paved over, that'd be true. But if a tree grows and eventually dies in a forest, it'll be replaced with new trees naturally, cancelling out the CO2 leaked from the tree dying. This C02 can also be stalled by harvesting the tree and using it in some way that stops C02 from being released for a longer time than natural.
I did some math on this, and if all the countries in the advanced world planted fast growing trees alongside all paved and unpaved roads, over 40 years, that could potentially be enough to sequester half of all carbon emitted by humans.
Given that carbon has a half life of between 20-200 years, and that we appear to be reaching peak emissions, and that a lot of estimates say our emissions should drop by 70% just given how often we replace power plants and how completive renewables are right now and are projected to be in the future -- it seems like planting trees really could be enough.
Could you share your math somewhere? I’m genuinely interested, and did your calculations take into account lowered cooling costs caused by tree shaded buildings?
It did not. But I think that's a HUGE consideration, as is the potential to reduce particulates in the air dramatically.
Here's a link to the discussion: https://news.ycombinator.com/item?id=20543605 -- on mobile so I can't figure out how to get the comment URL. If you're interested, just go there and search for my username -- onlyrealcuzzo. I'd love a second set of eyes on it. Not sure the math is right.
That is horrible for the ocean. Acidification will be killing off whole ecosystems and lead to drastically lower carbon sequestration by our oceans. As well as other horrible problems for us humans, who are still quite dependent on functional living oceans.
I think the OP is saying that most trees you plant now will be dead in 20-200 years and returning their carbon to the atmosphere through natural decay. Trees end up being a temporary solution. A permanent solution basically requires us to bury the carbon back in the ground where we found it in the first place, or in some other form that doesn't decay.
Numbers are important and should be discussed transparently. Lots of variation in guesstimates, fudging, simplifications, etc cloud the issue and give drastically different "good ways forward". So, please, correct my back-of-the-envelope estimate below:
E.g. from [1]: "Following the estimations of carbon stock including above ground biomass, the total stock in the studied chestnut forests could be ordered as follows: CF3 (105.8 t C ha-1) > CF1 (102.1 t C ha-1) > CF2 (76.3 t C ha-1). The pure chestnut forest CF3 characterized with the highest total carbon stock per hectare and only 20.6 % from it is accumulated in the aboveground tree biomass."
Chestnut is one of the best carbon sequestering forest options we have. Estimate (overly positively) that this capacity cycles over 100y. Fudge down the CO2 and CH4 release from decomposition. That gives ca 100 tC/ha over 100y, aka 1tC/(ha y) or 100tC/(km2 y).
Globally we have ca 35GtCO2 or 10GtC carbon emission per year. Current forests store about 15% of that, but we are currently loosing forests at a rapid rate, and we need to not only reach neutral but also sink the 100y or so of spewing we've already fucked up. So let's keep the number at 10GtC/y.
10GtC/y would then require 100E6km2 of NEW perfect assumption chestnut forest.
We have ca 500E6km2 of total land surface on earth. That means we need to set aside 20% of all land on earth for our NEW chestnut forest. But we don't have that much land that can sustain something like this. Forest grows less well outside of humid temperate to tropical regions. E.g. Antarctica, Sahara, the steppes, boreal forest regions, etc. E.g: All agricultural land, both fields and grazing, is 11% of total land area but over one third of all culturable land, the rest of which is already mostly forest. Even if we covered all growth-possible land area that is not already forest we simply don't have enough land. And we would be out of farmland.
Based on this back of envelope calculation tree planting is not a viable solution. It's a good step in the right direction, but nothing to get the crowds overly excited about.
Instead, e.g. azolla is around 15x more potent as sequestering growth stock than forests, and it grows floating on water. Genetically engineering azolla to grow fast in higher salinity would be a better way to combat climate change. We have plenty of ocean surface area. There will be downsides to such a solution, but compare with other solutions or the horrors of what will be if we don't act...
And I'm sure someone can cook up some gm-franken-algae that is even more potent.
My point, if any, is to make sure to actually run the numbers. Get different estimates then pay skilled scientists to get better estimates. Discuss the numbers, assumptions, simplifications. Don't get the general population stuck on low worth paths when they could start fighting for more valuable ones.
And I don't propose "stop planting trees". I argue that planting trees is a good thing, but only a minor item that is overshadowing more valuable options in the general debate. We need to get people to start facing reality to the point where they can start thinking about compromises. There is no "solution" that don't require drastic changes in how we use our land and live our lives.
Side note: nuclear is the only short term low land-usage footprint solution I can see, and drastic genetic manipulation biomass or vast nuclear powered direct capture are the only long term solutions I can guesstimate. Anyone that can show me interesting alternatives?
This is correct. At this point, we need to buy all the time we can, in addition to all other measures. In commercial forestry trees, are usually harvested when they’re 60 to 80 years old, but they remain net carbon sinks long after that if allowed to grow. Proper forest management practices minimize carbon re-emission from rotting plant matter.
The idea is not to just plant trees but to increase the number of trees on the planet over the long term so that effectively the CO2 absorbed does not go back to the atmosphere.
This is aimed at reducing CO2 in the atmosphere and has to go hand in hand with reducing emissions.
The goal is to increase the biomass. There is no reason it stays constant. More soil, more forest, higher trees.
I tried to find literature, but came back empty handed, on whether it is better to let tree grows on a parcel, or cut grass regularly and let it compost, adding biomass to it.
>whether it is better to let tree grows on a parcel, or cut grass regularly and let it compost, adding biomass to it.
Of those two options, trees. Compost does not sequester carbon in and of itself. That's a wishful thinking myth that is based on a lack of understanding of soil. Compost is organic matter, in various stages of life, death and decay. We want soil to have more organic matter. So people assumed adding compost to dirt would accomplish this. It does not. The organic matter is decomposed into CO2 and returns to the atmosphere. We need to increase STABLE organic matter in the soil, and compost does not do that simply by adding it to dirt. The only thing that creates stable organic matter is microbes living in the rhizosphere in symbiosis with plants. In order to increase soil SOM, we need more root mass. The way compost can help is to plant a forest or meadow and keep soaking it in compost tea so that the roots get deeper and deeper, expanding the rhizosphere and the depth of the soil. Normal roots will only grow as deep as there are symbiotic microbes, and yet those microbes will only live where there are roots, so there's a catch-22. We can use the microbes in compost, dissolved into water as compost tea, to get microbes deeper than the roots, so the roots go deeper, and then keep doing that. There's people with grass that has 20 foot deep roots from doing this.
So does that mean that at any given place, there won't be soil for deeper than the roots go? What happens to the soul if all the roots die or are removed (assuming it is not washed away by water)? Does it decay into CO2?
Different plants have different behaviours. Some sequester carbon well in the ground, others have near zero long term sequestration value. Some of the best are algae and seaweed that are allowed to sink to the bottom when they die. Plants that grow in bogs behave similarly. Chestnut is one of the best long term carbon sequestering trees.
One is carbon-sinks. This can be done by permanent new trees. Or by replacing trees and use the old wood or plastics for buildings. Or make carbon based usables and permenantly bury their waste in deep landfils that don't let out co2. Or by new techniques for sequestering carbon from air. Planting trees and letting them die is only temporary.
Second and most important though is getting more heat out of the planet than in. Focusing on carbon is one thing. But reflecting energy to space also works, e.g. by white roofs, or mirrors, or heat conducting materials that send off energy in frequencies not absorbed by clouds and co2/water/methane.
Fungi, bugs, bacteria, etc. break down the tree. Some CO2 gets released during this process and then CO2 gets released when the bugs die and decompose. CO2 also gets released if the dead forest burns.
I am not an expert (even an armchair expert), but I have to imagine it couldn't be that simple. When the trees die, they need to either be replaced, or self-replace. That means the land they are planted on needs to be protected. Further, when the trees die, they will release a portion of the sequestered CO2 back into the atmosphere. I wonder what percentage is re-released? Does this imply that we need an ever-growing number of trees to offset steady-state carbon emissions?
I think the tree survival rate is baked into the numbers, and most of these trees will outlive me anyway, so year-over-year CO2 I think would be fine. The EOL question is discussed in sibling comments and seems to be the crux of the issue. It seems like it mostly hinges on whether permanently increase the % of land that's covered by forest, or whether it reverts to something else once the trees die.
Based on wikipedia ([1], [2]), worldwide tree density is about 750 trees/hectare, with 4B hectares total (30% of land area). We clearly can't add another 7B to offset global emissions, but seems like a good marginal investment as long as there's room to grow that number. [3]
The real question is whether that $1 is enough to permanently "create more forest" Even at 5x the price it seems like a bargain for a lifetime of carbon emissions.
Even at $1/per tree, that is still extremely expensive when you consider that developing countries will need trees to offset their emissions as well. As an American ~$600-$3000 isn't a huge deal, but that outstrips the gdp per capita of many countries.
We should plant lots of trees, but we should also do everything else in our power in parallel.
New Zealand currently has a programme to plant one billion trees in the next 10 years, about 250 trees per person, so this doesn't seem at all unreasonable.
Yes, laudable in theory, but the current government hasn't delivered anything close. They should be at 184 million by now. They claim they are at 110 million. They estimate based on how many seedlings have been sold by nurseries, include seedlings "tranferred", which is a pretty sure way to overestimate. You'd think they would only count trees that the government was involved in planting, not trees that would have been planted anyways, but they take credit for everything anybody does.
They do have a programme to pay land owners for planting trees, but in minumum one-hectare units, and it's financially a loss. I own and live on farmland in NZ. I could turn a hectare into fully native bush and get their maximum one-time payout of $4,000. But the costs of native trees are expensive and the labour to fully plant up a hectare properly is not insubstantial. The $500 top-up payout for fencing doesn't cover the cost of fencing. Then I'd have to give up about $500 per year in farming income, permanently. It would feel good, but there is still a significant financial disincentive.
The government isn't really in a position to increase payouts. Taxes are about as high as the economy can handle and the government has lots of other projects to fund. If this is going to happen, it's going to be on the backs of individuals acting out of their own good will.
That's actually way, way less than I'd have thought. 500 trees isn't all that much, really. A nlick of 25x20 trees? What is that, an acre? (Genuinely asking... Giant sequoias will be different from sitka spruce)
You get customers to pay for the planting of 500 trees at $X/tree. This is treated as a long-term investment. 30 years later the trees are harvested and the "investors" get back X% of the value of the trees.
So they get to say they live a carbon-neutral life, and as a bonus, get to make some money.
My understanding was that trees are not the best way to go about this. Seaweed is best, followed by grass, then trees. To be fair, planting seaweed isn’t as satisfying.
It is domesticated - wild forms of grass are very different from lawn grass - they are more similar to the grains that we also domesticated from the grass family. Some of it is even closer to ferns in appearance (eg, wild dogstail)
Keep in mind that the 600-1000 number is for "tree age 0" which is a sapling about 6 feet (two meters) tall - the germination/survival rate for planting smaller saplings or seeds is much lower.
Yep, when my wife tree planted she'd carry bags of those on her hips. One member of her team planted a tree every seven seconds, while they were working in BC.
Which is why you outsource the tree planting to a place that has room for trees -- and it's more efficient because they can grow trees better than you can, anyway.
nationalforests.org, the Arbor Day Foundation... there are probably lots of good options.
nationalforests.org does reforesting of recently burned forests which are probably burning more frequently due to climate change. I don't think replacing forests that were alive when you were born should count as offsetting your personal CO2 emissions, if the idea is to have an actual effect it has to be new trees in new forests.
On a related note, today's New York Times has an article about the recent fires in California. Near the end the author states that the 2018 Camp Fire released
...an estimated 3.6 million metric tons of greenhouse gases that, as seems to happen at least once every fire season lately, was more than enough to obliterate the progress made by all of California’s climate-change policies in a typical year.
How long does such a model expect the trees to keep the carbon captured? Most (non-rain-)forests burn eventually, so for a long-term solution, we need to make sure that the carbon that is captured stays captured. I saw some mention of special grass as a good option, since it stored most of its carbon in its roots.
Planting that many trees is not what's required. What's required is growing and maintaining them. If they burn in a fire, you need to start over. If they get cut down, you need to start over. If the land they're on gets sold and redeveloped, you need to start over. Etc. I think this seems a lot easier than it is because the wrong language is being used to describe what is actually required. You need to bring into existence and perpetually maintain (even after your death) 172-572 trees. That is not easy.
Slightly tangentially related, for those of us who are into gardening and coding, there is a plant monitor made by Xiaomi called Xiaomi Flower Care that will monitor moisture, light, temperature, and soil fertility. It works over Bluetooth and can be purchased on Amazon for as low as $8 per probe but the vendors will often charge around $25. You see a lot of rebranded ones but they're all the same from Xiaomi. It works with their iOS (and presumably Android) app. Someone has released a SDK for it:
My plan is to use that and build a Raspberry Pi to monitor my plants. And later on maybe control the watering system.
Anyways, it's a nice cheap plant monitoring option. It was really helpful when I was trying to figure out why my plants were turning yellow. People were mostly telling me that I was either over watering or under watering, etc. Then the probes all told me that my soil has no fertility left so I just added some organic 5-5-5 fertilizers and my plants are doing great again. The nerd in me love checking the data every day but would ideal build a Raspi server to sync and display some graphs some day (using a Prometheus endpoint perhaps?)
If anyone has good advice on how to control a set of water valves using Raspberry Pi, please let me know! I know about GPIO but I would like to have a bus of some sort so I can add more valves in the future if needed. Maybe a USB solenoid?
Woah. This is awesome! I travel for work and keeping my plants happy has been vicious trial and error with passive auto watering stakes. I've been looking for a convenient sensor package so I don't have to muck around with wires. Jackpot!
There are many raspberry pi projects on reddit for the "microgrowery" community... I recommend having a search. I plan to set up an indoor tomato and herb garden using these methods.
For solenoids, I advise some methods like [1] so that you can connect a cheap and daisy-chainable relay board like [2] via SPI. Then you can control anything.
If you don't want to get down into the 5v to 3.3v mumbo jumbo, it may be easiest to connect an arduino or clone via USB to the raspberry pi. There are bazillions of documented ways to drive relays with an arduino.
With some caution: This works for specific plants only. I'm getting into cacti and other succulents as a hobby and I'm learning that minimal water and minimal soil fertility is actually the desired environment... which means such a monitor wouldn't help me. (This possibly also applies to bonsai- there is several overlapping growing mediums which makes me suspect this is the case.)
Think about using a bell siphon [1]. Its typically used in aquaponics with a constant stream of water being pumped, but the pump can certainly be switched with a relay/pi/sensor setup to allow for intermittent dry spells (depending on what your growing). Water can be pumped from a nearby reservoir or tank.
awesome! it would be good to have a database with information on what each type of plant you have needs and then alert if conditions are bad for that particular type
They work with the council and have organised the planting & maintenance of over 600 trees since 2012 (including the lovely Himalayan Birch outside my house which I sponsored last year).
I have also helped out here and there and created a 'tree map' a few years ago which has information on all the publicly owned trees in the Borough - http://maps.catfordstreettrees.org.uk/ (I actually happen to currently be in the process of updating the map with new data)
You can sign up for a service that will plant trees on your behalf. Do your own research, but these ones seemed pretty good and plant 1 tree per $1.
https://onetreeplanted.org/https://trees.org/
I've been liking Eden Reforestation (https://edenprojects.org/), which employs local populations to plant trees in deforested areas. Ecosia is listed on their Partner page, so I'd assumed that's how it works under the hood.
I'm interested in hearing about other projects, too.
Given the amount of provisos, conditions, and regulators required to approve of planting, it sounds to me like it is better to beg forgiveness than ask permission.
The rules presented in the article were just: "Don't mess anything up, and do it with permission by the land owner. If you plan to plant a ton, ask pros if that'll mess anything up."
If I understand it correctly, you can just look it up.
Woodland Trust:
> In England, planning permission isn’t needed if your project is under 2ha and in a low risk area. Check your area using the Forestry Commission land information search.
Then enable the Forestry Commission > Targeting and Scoring > Low Risk Areas for Woodland Creation layer.
At the very least, if your plan is to just beg forgiveness, it would give you a better argument that you thought it was acceptable and at least tried to comply.
I wonder if there would be a away for the government to allow people to purchase land at a reduced cost and tax-free (sales and property taxes) for the sole purpose of planting trees. Land purchased this way would be legally protected against the government's power of eminent domain/expropriation [0]. Sale of the said land would be restricted in the same way. If someone did want to develop the land, they would be allowed to do so only if they paid the difference that would have been accumulated over the years in taxes compounded with interest. The whole thing would sort of be like a U.S. 401k or Canadian RRSP, but for the environment.
It would sort of like what this Brazilian politician asked for here except the ownership of the land would be transferred, so it wouldn't be a sort of one-sided, long-term extortion [1].
One way to do this is through a conservation easement, which essentially splits off the right to develop some land and sells/donates that right to a land trust or the government. You retain ownership of the land itself, but this restriction becomes part of the title, so it runs with the land and binds you and future owners to its terms. In exchange, the donation is tax deductible (or the sale nets you money) and the easement also reduces your property tax since the land is now worth less (30-60%).
There are also less permanent versions where the owner agrees to manage the land in a particular way or according to a designated person’s advice (e.g., a forester). I think these are often for a fixed term (e.g., 10 or 25 years).
It’s so that a future government can’t sell that land to someone else to cut down the trees and develop it. That can still happen with private ownership, which is why I had the idea of giving concessions that would have to be paid back to deter it.
I really want to start planting trees because this planet needs more trees, it's not a joke or some hippy movement, the consequences are real. I just feel like doing so in the UK is a bureaucratic nightmare. Plus buying trees to plant isn't cheap.
I might just start saving up for land and planting trees there if I can.
> I just feel like doing so in the UK is a bureaucratic nightmare.
The way I see it, "making it easier to plant trees" is also an excellent action you can take, that can have even more of a positive impact than what a single person can achieve in terms of simply planting trees.
So if it's hard to do in the UK, you may find your time to be better spent making it easier for others (and yourself) to plant trees. And if you're on HN, you are like to have an entrepreneurial spirit; maybe you'll be tempted to start a charity or startup in the space.
Trees can grow from seed. Johnny Appleseed was an American myth about a man who planted thousands of apple trees by hand using pips as he walked across the country. Seeds can be extremely low cost.
Acorns and conkers can be gathered in their thousands each day in the British autumn.
Plating trees in your garden is always a recipe for future disputes with your neighbours, as petty as it sounds people get really uppity about keeping your shrubbery out of their view and boundaries. But that also depends where you live, I've seen a lot of trees cut down in my city over the past few years because they are a "nuisance". It's more likely that the city council just gave up on keeping them maintained or gave in on 1 or 2 complaints. Some of these trees were oaks that were most likely hundreds of years old and this is in public parks not close to any properties.
They are also trimmed down which is not as bad but not really helping the problem mentioned. Again these trees were hundreds of years old.
Planting trees in public spaces seems like a recipe for the council just taking them down. I'm not sure if it's even allowed by law.
Seeking permission from land owners would be a pain. For one they could just say no, which is fair because it's their land. But how do you go about finding out who they are in the first place?
I’ve found that rooting hormone vastly increases the number that do well. I’ve also been told but have not tried, that you can make a DIY rooting hormone by soaking green willow twigs in water than adding your cuttings.
I've started doing this as a hobby wherever I live after spending some time in the Bay Area and becoming obsessed with how cool huge redwoods are.
Growing saplings is slow and sometimes difficult, but one of the coolest things I've ever done was taking saplings I grew and then heading out into a reserve with scientists to plant them.
I feel like a huge understated challenge to these efforts is finding land that's protected / optimal for planting that will knowingly not be plowed or cleared within 60 years. Otherwise, it doesn't really matter how many trees you plant if they're all uprooted or killed before they even reach 6' in height...
There are a lot of people in this thread conflating 'mature' with 'in decline'.
Remember that there are many, many species of tree with a natural lifespan in their preferred environment that can be measured in hundreds of years. That's a huge time period between full-sized and 'slowly falling apart'.
A tree in decline may have heart rot. Every year its losing wood while making new. It's a fight against gravity and the elements. When the losses outpace the gains the tree loses integrity, major limbs start falling off, and eventually the trunk fails. If you told me this tree is carbon neutral, I'd have to take your word for it. But for the previous thirty years? That tree was socking away tons - literally - of carbon.
There are "mature trees" in the world today that will outlive the children sitting beneath them.
My wife and I have a property with a good bit of forest. It's mostly fir trees and birch. Every now and then I wonder if there's some way to increase the co2 uptake of the forest, but the question appears surprisingly complicated, and so far my conclusion has been to just leave it be.
There was an article posted recently that said the best way to increase the co2 uptake is by cutting down the fully grown trees and planting new trees. Full grown trees don't absord as much co2 as a tree that is still growing, and the needles that some trees drop make the ground acidic, preventing new trees from growing. The problem is that you have to find something to do with all the wood so the captured co2 doesn't get released from the harvested trees.
I'm not sure if that's true. Based on what I've read, older trees sequester carbon at a higher rate, according to [1]. I would like to see the counter claim.
Trees sequester carbon to the extent that they grow. They do very little of both at the beginning of life, they also stop doing both at some point.
There is a maximum rate somewhere in between, in an age that varies by orders of magnitude for different species. It's pretty meaningless to talk about young or old trees without context, except on that general way in that trees get old at some point.
I had a stupid thought yesterday that I need to run numbers on, but I wonder if following would be possible:
Allocate some large area of ground for planting fast-growing trees. Dig a large and deep hole in the middle; something like 20 meters in diameter x 500 meters in depth. Let the trees grow; when they're mature, cut them down, throw into the hole, and throw a bunch of dirt (from the mound you made by digging the hole) behind them. Plant new trees, rinse and repeat until the hole is full, then dig another one somewhere near. Would that even make sense as a carbon sequestration facility?
No, because the buried wood would decompose. Decomposing wood releases its stored carbon as carbon dioxide, which will slowly evaporate through the covering dirt.
One scheme that actually would work is to convert the wood to coal, then burying it. That could be done without adding any energy by using old-fashioned methods for charcoal burning.
Because charcoal is chemically inert, the buried charcoal should stay put for up to a few hundred years,rather than a couple of decades for the decomposing wood.
How slowly though? Intuitively, I would think that trees piled wide and 20m high and covered over would still be mostly there in my lifetime. Is this wrong? (genuine question)
500m high is another level. If it took, say, 1000 years for them to decompose fully and release their CO2 in to the atmosphere, that's still potentially useful even if its technically net zero.
We really only need to get past the next 100 years.
If/where suitable mines exist, railways may still exist and might be feasible from a carbon standpoint with the newer diesel locomotives or using an electric locomotive.
That said, you aren't going to make a considerably dent in the CO2 emitted in a given time period doing this. Used in combination with dozens of other things though...
I'd imagine many such plants deployed around the world. I wouldn't expect it to be anywhere close to a complete solution, but it's the easiest way to start doing carbon sequestration I can think of.
> Full grown trees don't absord as much co2 as a tree that is still growing
This does not seem logical. Two cars emit more C02 than one car. Two leaves will absorb more CO2 than one leaf. A 2m young tree will never be able to consum so many CO2 as its older 40m high grandparent with a x10000 mass (mass that must be maintained).
>This does not seem logical. Two cars emit more C02 than one car. Two leaves will absorb more CO2 than one leaf.
Mature trees grow much, much, slower. The wood is (largely) the captured carbon so once a given species reaches a certain maturity, harvesting it for lumber to be used in construction and planting a several year old tree would be the most optimal.
Some actually want to genetically engineer trees that grow much faster to do this (although faster growth generally means softer woods, but simply drying the wood and storing it in mines would buy you many decades to centuries before the bulk of the carbon was re-released).
Trees don't absorb CO2 just by existing- they absorb CO2 by growing. The carbon from the air is converted into structure, body of the tree. When the tree stops growing, the CO2 stops being absorbed.
Cutting down the tree and using the wood for long-term storage contains all that CO2. Planting new trees means growing trees that absorb more CO2 from the air.
Plants not only make wood, they make nectar, sugars, ambar, they make alkaloids, and they make thousands of seeds also.
Some hard nuts remains have been found after 3000 years. They will survive for as many time than wood or longer. A big walnut can produce 160 Kg of nuts each year. A sequoia can produce a number of pine cones that I can't quantify, but would be probably measurable in thousands of Kg/year. Easily
Even more, upper members of the Plant kingdom produce a very special substance. One of the most inert polymers found in the nature that is much more desirable than wood for our needs of stabilising climate. Its degradation time can be measured in millions of years and appears fosilized or semifosilized in all continents and all ecosystems, with or without trees. Is called sporopollenin, and is the extra hard and waterproof material that makes the outer layer of pollen grains.
You don't need a tree to produce really hard pollen. A humble daisy can sequester carbon in a powder that will easily remain structurally intact for the next 1000 years. Everybody that has a garden and has cultured a big conifer knows that males of this creatures release copious amounts of the substance each year. Also old plants. _Specially_ old decaying plants that are about to die and invest all its reserves on reproduction. Maybe its time to start quantifying it.
Therefore your statement that plants only sequester CO2 when they grow is clearly false. If your maths and calculus do not include nuts and pollen, and do not include soft herbs, flowers and annual weeds they are incomplete, and most probably wrong, IMHO.
And two leaves will also release more CO2 than one leaf, once it's on the ground, decaying.
Trees don't make carbon magically vanish, trees store it in cellulose, aka (more or less), wood. A tree that doesn't grow more wood does not store more carbon, and there is nothing to be "maintained", mass does not just disappear.
Not exactly, but they also don't grow boundless (some do, but that's because the meaning of "growth" and "reproduction" mix, for all practical reasons, they become many trees). The growth rate slows down superexponentially at some point.
it's probably a 2 (or more) factor optimization problem. Because even if large trees don't absorb as much, they are still blocking sunlight and converting at least some (how much, I don't know) of the photons into photosynthesis instead of heat. The sweet spot would probably be a medium-size tree.
I don't see how 1.5 billion trees is enough to offset the UK's carbon emission rate. If you go by a tree sequestering a ton of carbon over a 40 year lifetime, and the UK emitting 368 megatons per year... you're sequestering on average 37.5 million tons per year (less when they're young, more when they're old), which is only one tenth of what the UK emits in one year.
Plant 15 billion trees and then you're carbon neutral, on average, for the 40 years, and carbon negative if they live longer. But isn't that like planting trees on half of the land of the UK?
Planting trees can only ever be part of the solution, but it gives you time to greatly reduce net CO2 emissions while you figure out how to reduce gross CO2 emissions effectively.
And out of all countries the UK is the one of the few that could actually plant half it's land area in trees.
The slow initial growth of trees makes me wonder whether we'd be better planting fast growing crops like bamboo and hemp which can be processed into long term materials like fibreboard and bioplastic or added to concrete.
and seaweed near areas with ocean access. I wonder if you could have wastewater treatment plants that feed seaweed (in a large enclosure with seawater access, done responsibly), then harvest the seaweed, dry it, and send the carbon straight to mines for sequestration.
More simply, perhaps farmers could be encouraged to sink waste carbon in the same way. Corn farmers could be encouraged to send the husks to sequestration instead of burning (I know they use the ashes as compost, so there are downsides). Or hemp, as you said, strip the leaves from the stems and send one or the other to a carbon sink.
Rather than immediately sequestering the carbon, it seems to me that it would make economic sense to use fibrous plant materials in products.
By taxing competing non ecologically friendly alternatives like fossil oil-based plastics, and sending carbon-containing products to landfill, a greater financial incentive is created for growers, and carbon is sequestered from the atmosphere rapidly and long-term.
Is the carbon sequestered when the paper bags are sent to landfil, or do the bags rot releasing a mix of co2 and methane, making this a negative result because of the extra warming effects of methane?
Anaerobic decay of carboniferous matter produces much less carbon loss as gas than aerobic decay. Captured methane is destructively utilised, reducing its greenhouse gas concerns. Processing fibre crops into particular bioplastics can also reduce potential for gaseous decay.
This seems favourable when compared to trees which produce large quantities of openly decaying matter (e.g. fallen leaves) throughout their lives, and unless lumbered, will almost entirely decay when they die.
Processing and transport requires energy which is unlikely to be renewable. To maximize impact I think we need to find some efficient system, perhaps algae or GMO plants or weeds, that sinks carbon straight into the earth. Perhaps very verdant places like Minnesota, residents could be encouraged to collect deciduous leaves each year and round them up for sequestration (which again requires energy). Or renewable and nuclear power plants could use all of their excess power toward some kind of machine that scrubs co2, which becomes a solid at relatively high temperature of -75C (compared to liquid o2 or n2).
We could artificially capture arbitrary amounts of carbon using nuclear and renewable power, but I think it's important to consider how such activities would be paid for.
It seems more politically feasible to me, to incentivise ecologically healthy consumption through taxation (e.g. carbon tax; fuel duties; severance taxes), than to fund grand reparative projects.
they should be paid for by the industries that caused the pollution: oil and gas, automobile, manufacturing. I don't think there is any dichotomy regarding encouraging healthy consumption. Even if we were carbon neutral today, how are we going to siphon back the excess carbon that has been released over the last century?
Also we should stop cutting down the existing forests. Brazil and Canada have both been in the news recently for clear cutting their rainforests (yes, CA has inland rainforest!)
Brazil is different they are being cleared for agriculture but it is hard to tell them they can't clear forest to become rich when most of the rich world did that before them.
Canada replaces 500 year old rainforests with saprolings. We do a decend job rotating tree farms, but there isn't any way get back our ancient trees (besides waiting a few hundred years).
Could we plant trees in parking lots? A law must be made. In the US especially West Coast (Seattle) for example and also in Germany a lot of flat space has been taken by parking lots. Its actually crazy seeing these huge parking lots. Could we plant verticle wines and change the geometry (introducing gradients to add area for a tree - simple pythogoras concept) to add space for at least a tree per car slot or maybe at times even more.
Many places in the US having zoning codes requiring trees or other plantings in parking lots of certain sizes. Success is mixed. Where I live a big box store will typically be built with a bunch of small trees planted which don't have adequate area for water to reach their roots. They will die in a few years and maybe be replaced by more tiny trees which die. So, that zoning might want to be revisited.
Writing laws to ensure outcomes with trees is hard. Our old suburban community, generally covered in mature trees, made rules that if a developer is going to tear down a house and build a new one the trees must all be inventoried, only a minimal number are allowed to be removed, the rest get fences around their drip lines for the duration of construction to protect their roots and at the end they are checked to make sure they weren't injured. Significant fines are involved for accidentally taking a tree… So now before a homeowner sells their property to a developer they "do a little landscaping" i.e. cut down all the trees except maybe some small ones on the lot lines. Problem solved!
Yup but its like a cat mouse game. There never will be no crime so the in the government laws must keep evolving, just as the thieves get more innovative. But the laws are needed. In Germany at least now they are taking climate change seriously. Munich has invested a lot in public Transport and by 2030 it would really at a good level. The parking lots Story I will make a Blog soon with preise carbon calculations so that its advantage us both for the Business and the climate.
Many of my 4 year old Spanish Cedar trees (cedros) are already 20cm (8") diameter at chest height and ~15m tall. Planting hardwood trees in the tropics is one of the best long term investments you can make, especially if you plan to have furniture etc made with the wood. Some types of trees are ready to harvest in 5 years, others in 10, others in 20, others in 40+ (for your kids)
I've planted about 30 hectares so far, will do another 15ha this year. To keep maintenance costs down, you can plant them in contour rows along with closely spaced leguminous trees like inga edulus to shade out the weeds below.
Selecting trees that are hardy against insects when they are young is a good way to go (cedros and mahogany are not, need spraying..) I'm not a fan of teak, eucalyptus or pine being planted in the Amazon, I think fast growing native species are best.
If you do the math, the numbers are really good. And it's good for the animals. And climate.
Where? Not where it will grow up into utility lines, or where it will fall into utilities or onto a structure.
What type? Small and strong species that will not uproot, snap off or shed branches in a windstorm, and will tolerate heavy loads of ice and/or snow, depending on your climate.
trees don't need to be in perfect shape to sequester carbon. breaking off branches is part of nature's process. and they can be trimmed to avoid powerlines since you have plenty of warning. I think the biggest concern is for those who live in deserts where water is scarce.
If the aim is to sequester carbon, then planting trees seems to be only half the solution. We also need to prevent the captured carbon reentering the atmosphere by combustion or decay. It seems to me that it would be beneficial to landfill as much wood as possible to capture the carbon underground and limit aerobic decay, and rather than recycling wood products, sustainably harvest as much new wood as possible. In this case, the best place to plant a tree would be where it could be most economically lumbered, and the best kind of tree would be that most useful for industry.
A lot of farm land seems ripe for planting trees. Does anyone know of any organisations who work with farmers in the USA, Europe, Oceania, Asia, Africa or the Americas to help reforest farmland?
Trees can be planted a lot easier than you probably think (e.g. cuttings from existing trees). Trees grow best in established forests or areas with shrubby growth, as this indicates the soil is generally more fungal than bacterial, which trees prefer.
Check out the efforts of Akiva Silver and Geoff Lawton on YouTube. Also:
If you want to plant lots of trees cheaply, and watch your forest come to life we created a platform for exactly that. We don't take a cut of your money to pay ourselves either. We just want to let people achieve amazing things and grow billions of new trees.
It's Offset Earth - https://offset.earth/
The only problem I have with that is that many areas that are grassland in the UK now may have been heavily forested and were denuded of trees prior to or during Roman colonization.
Think about it, this is in Britain right? Grassland that has never been ploughed is going to be pretty rare, probably some kind of old ecology that shouldn't be converted to forest willy-nilly. That's my guess anyway.
Presumably because the Trust are tasked with conservation of nature, they cannot recommend converting one land use to another, because that would run contrary to their task.
How about like, urban farming? If I was to grow my own tomatoes and peppers and onions, like, to make a badass salsa, is that helping sequester carbon or no?
I admit my front lawn is like...embarrasing. It's nothing but grass and one single tree. If I was to really go nuts on it, would that help?
It wouldn't be such a bad future if everyone's lawns were required by law to have a few trees.
I recently looked into this as well. What I'm worried about (as opposed to a more expensive method like Climeworks offers) is what prevents people from ripping out those trees next year? The planting companies never seem to be the owner of the ground. They don't even guarantee a single year.
I've been wondering about various carbon sequestration methods myself and am glad to see these topics on HN since it is an opportunity to harvest relevant knowledge from the community.
Apologies for tangential topic, but give me a sec and it'll try to tie it back to some other discussions happening here - has anyone here heard of "Cryo Carbon Capture"?
This seems to involve feeding the exhaust of a power plant into a process which cools the exhaust to the point where CO2 dry ice (and other pollutants) desublimates out of the exhaust and is then extracted for various industrial/commercial applications.
I am curious about this model if it feasible then couldn't this also be used on the exhaust stream of a heater for pyrolysis of fast growing trees, grasses, etc. creating biofuel and biochar?
You can use biofuels to heat the pyrolysis and biochar to sequester carbon in the soil, while also improving it to grow more biomass for sequestration. The cryo-capture handles your CO2 waste streams and further captures carbon in a cold sink (also useful for refrigeration and can maybe act as a "battery" when combined with a Stirling engine?) which also produces CO2 which can be used to enrich biomass grown in greenhouses and has plenty of other commercial uses.
If you add solar and other sustainable power inputs to the cryo-capture process then what you have is basically a farm which creates useful carbon-based products from the atmosphere using plants and basic chemistry... and here is where I hope someone with more knowledge will point out why this isn't already a thing, likely due to some serious inefficiency I'm overlooking.
> This seems to involve feeding the exhaust of a power plant into a process which cools the exhaust to the point where CO2 dry ice (and other pollutants) desublimates out of the exhaust and is then extracted for various industrial/commercial applications.
Based on what you said, the dry ice would sublimate and just re-release the carbon into the atmosphere. Or did you have a different place for this carbon to go? If so, how are you planning to keep the dry ice cool, and how are you planning on producing it in the first place?
The dry ice itself would be stored in well-insulated containers, and cold generated from these containers would be useful for refrigeration with the CO2 that does sublimate out as the containers heat up being feed-stock to enrich greenhouses, with the rest would being recycled into the pyrolysis exhaust, and thus back into the dry ice production.
One of the things I'm curious about is the efficiency of the dry ice production at various CO2 levels and the physical quantities of material that would be expected from such these kinds of processes.
The general idea is that you would be creating a system for accumulating/concentrating carbon as CO2 solid/gas, as well as in biomass, and at the same time creating two large energy differentials that could also be put to work. The major input to this system (assuming the numbers can work) would be photosynthetics and photovoltaics.
AFAIU most of our industrial CO2 (for dry ice, soft drinks, etc) comes from refining natural gas exhaust. From there, if you want to make a dry ice block, you have to take it through a very energy cooling process (similar to how air conditioning works) to create a liquid, and then through a second compression and cooling process to turn it into a solid. It is likely that the process of turning a given volume of CO2 into a solid would produce more emissions than it sequestered. You cannot assume that green energy will be used for this sequestration because if green energy were available at this scale, you wouldn't have the CO2 on your hands in the first place.
On the demand side we already collect as much CO2 as we need from e.g. natural gas power plants. We don't have a use for any more. It will just sublimate and be re-released into the atmosphere, or into some containing vessel.
As for tree planting - absolutely necessary, but without a political solution, it won't do much but buy a bit of time. And that is ONLY true if we stop ongoing, accelerating deforestation.
A political solution would likely be better than individuals trying to plant a few trees.
I don't understand this feel-good obsession with planting trees. They plant themselves! Just stop cutting grass and they will come and if they won't, planting them would probably not help anyway!
There are about 3 trillion trees for a population of 7 billion people for an average of 428 trees per person, so that means you have to make up the delta of about 172 to 572 trees over the course of your lifetime to erase your carbon footprint (of course, young trees don't sequester as much carbon, so your footprint will still be positive for much of your lifetime - but as the trees get older, they sequester at a higher rate per year, which eventually gives you a negative footprint). This projection was based on the CO2 sequestration per year and the average survival rate documented in [1].
[1] https://www3.epa.gov/climatechange/Downloads/method-calculat...