Forests with multiple tree species are more effective as carbon sinks | Hacker News Reader

Forests with multiple tree species are more effective as carbon sinks

phys.org

128 pointswglb67 comments

I've had a die off of the pinyon pine trees on my small lot, from bark beetles, and have lost about half of them. It's been a big job to clear them out. During that I've noticed that they are more likely to survive when closely paired with the other common tree in the area, a shaggy bark juniper. The junipers are resistant to the beetles and seem to bestow some of that on nearby pines.

It was 50/50 pine/juniper, now it's around 25/75, all due to loses in pine. Without the juniper the loss could have been another half as much pine. So my yard is an example of multiple species resulting in more carbon capture.

Junipers are fascinating trees to me. Most people find them ugly, (and they certainly can feel that way next to a beautiful Maple) but they are quite remarkable trees. I've seen junipers get horribly torn up by deer antlers, and survive wounds that would have ended a Cottonwood and especially an Ash or a Maple. They are survivors!

Even if they are ugly when they are living, they're wonderful to behold when they burn! I would hazard a guess that they're unpopularity with people stems from their popularity with ticks.

Simard showed that birch trees favor a more benign fungus in the soil over a pathogenic cousin. When you cut the birches, within a few years the balance shifts and other trees start to succumb.

I wonder if the pinyon is working like that or if it’s polyphenols of some sort being exchanged through the food web.

Are there other forms of long term natural carbon storage than hydrocarbures or shale gas? Because a wood branch eventually decades and reemit the carbon, if it doesn't get buried deep in (usually sea) ground

New forests are long-term storage.

A single tree will eventually die, decay, and re-emit carbon. However, it will quickly be replaced by new trees that re-absorb a similar amount of carbon. Despite some amount of carbon exchange every year from growth and decay, the forest as a whole stores a huge amount of carbon as long as it lasts.

Maybe not stable on geological time-scales due to things like disease, disaster, or continental drift; but certainly extremely valuable on the order of millenia.

Exactly - people seem to get a little caught up in the ‘carbon offsets are BS’ narrative (which there is a lot of truth to - a lot of credits in these markets are grifters selling sham credits, and offsets in general won’t work long term if we don’t massively reduce things like fossil fuel use). But taking it too far can mean they aren’t able to quite grasp this about how the forest works.

So you get weird, wrong takes like “because trees eventually die and decompose, a forest stores zero carbon on a net basis.”

But you’re spot on - the new forest will absorb a certain amount of carbon, and then should basically reach a steady state where new growth trees are absorbing a similar amount of carbon as the decomposing trees are releasing (more or less on the short term, but should roughly even out over the medium term).

Of course, there are sometimes things like bushfires, but ideally forest regrown in an area where there was a bushfire re-offsets that (but you can’t claim that against other carbon you release, only against the carbon released by the bushfire!)

See also forest succession, where pioneer trees grow and die, intermediate trees grow on the stumps, and apex canopy trees grow on their stumps. That’s a process that’s anywhere from 80-400 years in the making, and each species holds more carbon than the previous. That’s a long time for us to get carbon neutral.

One that’s been replaced with clear cutting, which removed the nurse logs the next generation would typically indirectly consume.

All plant biomass is equivalent to 45 years of global carbon dioxide emissions at current levels. You have to plant a lot of trees to make a noticeable dent.

new & long-term are 2 opposite terms

by long term I mean a 10k year scale for example (civilization scale), not 100 years (human life scale - mid term), or a few years (short-term)

The North American forests existed for at least 100,000 years, many times longer than recorded history. Is that not long enough for you?

If we were to reforest those areas that were cut down ("new" forests), that's an extremely effective long term carbon sink.

Yes that forest existed for many years, produced coal, oil, shale gas, that's the long-term storage

If the forest now regrow, it's a short term storage (added with the long-term effect, that will take more time to settle, but it's a continuous process, so it's good to have too)

https://en.wikipedia.org/wiki/Biochar

If we get serious about producing biochar, we could sequester many gigatons every year of atmospheric carbon in biochar for addition to the soil. There, it would remain stable for thousands of years and improve soil microbiology, increase soil moisture and plant growth, which in turn would provide more feedstock for additional biochar in addition to other valuable things like food.

On top of that, some companies are studying adding biochar to concrete (replacing some cement). It's really interesting because it lowers CO₂ emissions twice (cement creation + biochar CO₂ sequestration). It's starting to be tested a bit in France. Take a look in google scholar because it's really interesting and will be big IMHO

Not 100%; some of it ends up in the soil. And then more soil ends up on top of that, and so on. That's where oil and coal came from. Just accumulated deposits that didn't end up in the atmosphere. Over many millions of years.

Half of a tree is below ground, and that breaks down slower.

And in fact there are situations with root fusion where some roots from one tree get adopted by neighboring trees. You can see this occasionally with stumps that heal over without any trunks at all. I have seen three examples around here and recall the location of two (on a hiking trail less than 200 ft apart).

I grew up with the idea that the root system of a tree mirrors the branch system, but that's not really how it works. Roots don't penetrate all that far down, and are more spread out across the surface, but certainly don't hold half the mass of the tree. The bigger the tree, the more this is true. A giant redwood does not have that much biomass underground as it does above it. The soil richness is generally pretty poor in those giant redwood groves.

Redwoods and a few of the other big trees are unusual in that they stop trying to pull 100% of their water from the ground. It’s hydrologically impossible. Some of it comes from epiphytes like moss, higher up in the canopy. Absorbed straight through the bark or via adventitious root hairs.

Not all of the soil carbon from tree roots is in roots. Without the tree, more than just the roots disappear.

What did the massive, global, currently undiscovered civilization before us do? Something tells me the giant oil and coal fields were their solution and we're currently digging that all up and utilizing.

(this post is satire)

Rock. Silicates absorb CO2 through weathering. Olivine absorbs faster in seawater. Weathering is one of the slow non-biologic sinks for CO2.

But it is possible to make it work faster by crushing olivine and dumping it in shallow ocean.

Not exactly the answer to your question but some idea of the scale of the problem https://www.sciencenews.org/article/where-earth-stores-its-c... TLDR, it's estimated the vast majority of carbon on Earth above the crust is in the ocean.

Soil.

https://www.nature.com/articles/s41467-019-08636-w

"Soils store climatically significant amounts of carbon (C) as soil organic matter, globally about 2.3 times greater than the C in atmospheric CO2 and 3.5 times greater than the C in all living terrestrial plants1. However, prolonged cultivation accelerates the decomposition of soil organic matter and can cause the loss of 20–67% of the soil C in an agricultural field2,3,4. Between 1850 and 1998, global agricultural cultivation led to the release of ~78 Gt of C from soil as CO2 to the atmosphere4, with ~133 Gt of soil C so released since the beginning of agriculture5. Since the current global annual CO2 emissions from fossil fuels and all other sources are ~10 Gt of C6, soil C sequestration has thus been proposed as a plausible partial climate mitigation strategy that might buy time while low-carbon technologies are being developed and adopted7. Indeed, a recent international initiative has set a target of increasing global soil organic matter by 0.4% per year to help negate some greenhouse gas emissions"

Note: papers about soil use Carbon mass, not CO2 mass, to convert 1kg C ~ 3.67 kg of CO2

What if Humans focused most climate change efforts into reforesting the Sahara desert?

Build up a system of desalination, irrigation and slowly turn the desert into grassland as a giant carbon sink. Lots of hard work, and it will take a long time, but why try to reinvent the planets natural systems when it comes to climate change?

The situation in Sahara worsened even more with climate changes, so I think it's best to act globally, as everything is connected, not on a specific & hostile place which will require a lot of efforts (so pollution since I doubt it'll be done without any machine, plastics, oil). Best to work on individual level, spending much less, voting well, let tree grow where they can grow more easily instead of putting tennis courts, swimming pools, oversized houses, etc..

High altitude dust from the Sahara acts as fertilizer to the Amazon.[1] The biosphere is a complex, interconnected system.

1. https://www.nasa.gov/centers-and-facilities/goddard/nasa-sat...

Yeah... everything is way too complex and interconnected for any of these "let's just do X to solve everything at once" plans to work.

I don't get how people can still be so guilible after we basically shown over and over again that we don't have much control on what's happening, virtually every breakthrough we had brought more issues we have no idea how to fix in the long run.

Not sure I subscribe to a totally fatalistic view here. Complex and interconnected systems can still yield solutions to careful study, and even without total foresight and control, some outcomes can be preferable to others.

Basically monoculture is horrible for everything but industry.

Unless we mean in different places, I'm pretty sure it's bad for industry too;, ex. a part only having a single supplier is a risk to every downstream consumer of that part.

Including the authors of the study, we all want this to be true but from what I can tell by reading the discussion in the article the "aboveground carbon store" of monocultures might actually be hard to beat. Their data appears to be shaky and we should take other factors into account to encourage diversity.

Monocultures are the spherical cows of horticulture.

It’s also a misnomer because all of those pest species count as the biosphere. The harder you try to grow only one plant, the more non-plants you end up growing.

Sounds like a spurious correlation to me. They found 4 species forest 70% better than mono species forest but by 6 species, forests are back to mono forest levels.

Biodiversity generates stability

Mindless money that's being poured into carbon capture projects, would help grow and maintain forests for at least 10yrs. A recent example like Heirloom that just started its facility and would only capture 1000 tons per year. It took them 4yrs and $50M+ to build one facility. Even if they somehow were to build 1000 facilities annually, they would only capture 10M tons of carbon. Also think about the carbon they would release by building those facilities. We need to remove 2 billion tons of carbon per year at current levels of pollution. Carbon capture projects are just another type of climate grifting like carbon offsets etc.

People are carbon. Could we remove them?

I think that's the plan.

People are neutral, unless they spend money (which is more or less a unit of pollution & carbon-emission)

Every 15 people is a ton (on average). And while we can't remove 20 billion people, 6 billion or so would make a nice dent. Additionally, those people consume energy. Once their consumption drops to zero, we see additional savings.

I think I really have stumbled upon a solution here. The planet will be better off for it. What's wrong with this idea?

you can reason the same with ants

but ants are like a human who doesn't spend money, or like a bird, they are sustainable, no need to remove them

but no even need to be extreme/binary, 8 billion humans who live like a 3rd world country-side human and spend a little money is totally sustainable without any issue, because that's equivalent to less than a hundred million 1st world humans

Birds are known for their nitrogen sequestration.

https://en.m.wikipedia.org/wiki/Guano

Great, but that's more or less the same with other feces, composition vary in carbon or nitrogen, but they're all great fertilizers

Be careful there, that doesn't sound nice.

An increasing number of countries have declining birthrate. This slowly, steadily gets us in that direction but not without demographic problems and significant economic disruptions. Let's try keep it peaceful...

There is no such thing as a carbon neutral human. We're ~20% carbon by mass.

I do agree with your point about money though--economic activity is the primary cause of our excessive carbon footprint. We need to change how we practice money such that "number go up" type thinking correlates with progress toward agreeable goals instead of correlating with the consumption of nonrenewable resources.

For multiple reasons we need actual foresters to build ecosystems, not just plant a bunch of trees. They also need to be built to maintain themselves, not be reliant on continued investment. Bonus points for building ecosystems that support a small amount of logging.

Fully agree with this. Continued investment with forest ecosystem maintainers in place is best solution.

Best solution is reducing drastically our footprint, our consumption, instead of helping to grow forests, subsidizing gree businesses, why not heavily tax plane & car industry/usage, incentivize low-footprint lifestyles, educate?

You're not gonna win if you only work one way.

We can both reduce our carbon footprint AND plant trees.

Trees grow by themselves above all if we reduce our footprint (and stop nonsense things like swimming pools, oversized houses, tennis courts, concrete everywhere, ..), Focusing on reducing footprint has such a big impact, it's easy to cut by half one's footprint, and if that's done largescale, it's basically as if the world population is divided by 2 instantly

No, because this solution to environmental problems is "our impact on the environment is going to cause a global depression and catastrophe due to changing climate! we must try to stop this by causing a global depression and catastrophe ourselves by drastically reducing consumption!"

Consumption that dumps carbon in the air needs to be replaced by consumption that doesn't. Power needs to be solar/wind/nuclear, cars need to be electric, things which are done cheaply with hydrocarbon sources need to be replaced with more expensive things with sustainable sources.

Trying to make people significantly lower their standard of living with fear of future consequences will not work. It just won't. In two ways... one: a lot of what's happened has already happened and is inevitable, there's no turning back from a few degrees of warming, oceans rising, and climate patterns changing; two: people won't do it.

Trying to chase the line of solving environmental problems with consumption reduction is pissing into the wind. You have to try to do things which will actually have effects instead of trying the impossible.

It's very easy to divide by 2 one's footprint, without a loss in "comfort", my lifestyle is even 1/20 of the average, and I'm totally fine, but definitely not asking average people to go that far, it's just to show it's possible

If that's done large scale, it's as if the world population were divided by 2 instantly

Reducing our footprint would help a lot tree to grow (they don't really like pollution and climate changes), but obviously we should still help forest to grow and migrate north (in north hemisphere), it's just not where the big win is currently

Maybe "the world" needs to pay to countries with large forests (like Brazil) to maintain them, instead of paying them for cutting them down (lumber, agro, resources)

The opposite, "the world" needs to put trade sanctions and large tariffs on countries which have exports which are cheaper because they abuse the environment (deforestation, fossil fuel powered, etc.) and while they're at it: labor (wage slaves, child labor, unsafe practices, actual slavery).

Don't pay corrupt countries to be less corrupt, charge them a fee that makes bad practices more expensive than good ones.

This is a game. Dictators and developing economies are good at taking incentive payments and pocketing them.

Regulatory capture. Too much of the population of “foresters” is bought and paid for by the tree farming industry.

Asking foxes to grow more chickens definitely gets you more chickens but you don’t get the benefits, they do.

They spent money here to put up boxes with special moss in around here.....

And when you think that they put carbon into greenhouses to make the plants grow more.. I reckon extra carbon just means extra growth in plant life. Ie the plants are a natural balancing mechanism.

Interesting.

I looked up the world consumption of lumber in 2018 (pre-pandemic stuff). ~ 2.2billion cubic meters, a cubic meter of wood is ROUGHLY(really depends on species) 0.55 tons.

So If we doubled lumber production (which would help housing/construction and a lot of other sectors) wed at least offset the carbon created by roughly half.

Still wont come close to solving our CO2 emission issues but interesting because we could "get something" from the lumber vs just storing CO2.

Assuming 100% carbon capture into wood weight which is not realistic but I think it's a good thought exercise.

I'm not saying you are doing this, but don't confuse Lumber production and forest growth. Increasing lumber production decreases forest growth.

we need to increase forest capacity for lumber production first.

I don't think you understand how trees work as carbon sinks. You're destroying that potential by cutting them down.

Trees actually carbon sink via growth aka creating wood. The CO2 they breathe in is turned mostly into growth / basic functioning.

So no, you are NOT destroying the potential. In fact, if they grow and die and rot they are going to essentially release all the CO2 they captured.

https://extension.psu.edu/how-forests-store-carbon

So converting mature trees into lumber is essentially locking out the carbon capture more dramatically, especially if used in long term uses like housing etc. Being turned into firewood would be drastically bad for CO2 capture.

What am I missing that makes you think I don't understand?

Only if the tree rots. If you turn it into treated lumber and build a house with it…

No. A dead tree log does no longer bind any more carbon.

I read that story as well, and while the company does promise increases in efficiency, the whole thing seems like a very expensive way to do very little.

Based on light googling, a mature tree can capture about 50lbs of carbon a year [1]. Assuming a few hundred trees per acre [2] you could get, let's say, 5 tons per year in the steady/mature state. Small numbers, but it adds up. Leander, TX is a suburb of Austin that sprung up in the last 50 years. It's a useful measure for me as 1) I have some intuitive comprehension of the size (37.5 sq miles) and 2) it was an area slowly developed over the last 50 years. If it were reforested (you wouldn't want to do this because, you know, people live there), we might get 100kton of capture a year (guesstimating). Repeat that 170,000 times and we can get back to the net emissions of the year 2000 - a 17gigaton reduction per year.

Of course, that would require planting an area double the size of the United States.

Anyway, that's napkin math and I hope I'm off.

1: https://www.usda.gov/media/blog/2015/03/17/power-one-tree-ve... 2: https://bugwoodcloud.org/resource/files/27435.pdf

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