Naked Science Forum

Life Sciences => The Environment => Topic started by: iRock on 18/12/2013 14:51:45

Title: How much CO2 does a tree consume per year?
Post by: iRock on 18/12/2013 14:51:45
I know 1 mature tree can store 48 lbs CO2 per year and give 260 lbs O2 per tree per year . So exactly how much CO2 1 tree use per year for photosynthesis and storing process or just only 48 lbs ?

I know grassland absorb 2400 – 3600 lbs CO2 per acre per year and create half kilogram O2 per 1 square foot per day . So exactly how much CO2 grassland use per year for photosynthesis and storing process ?
Title: Re: About CO2
Post by: CliffordK on 18/12/2013 18:59:52
It is not quite clear what you are asking.
If you are asking on the globe...  then it is difficult to say.

There are about 57,308,738 square miles on the continents on Earth.
640 acres per square mile.

That gives about: 36,677,592,320 acres, including forests, farmland, deserts, and glaciers.  However, if you say 1 ton of CO2 per year per acre, then one comes up with 36 gigatons of CO2 being absorbed on the continents, plus what is absorbed in the oceans. 

However,
All plants are balanced with decomposers.  Even the trees eventually die, and are decomposed. 

So, while about 36 gigatons of CO2 is absorbed every year, the vast majority is released again by the plants in a cycle. 

Are your numbers off a bit?
The plants and trees absorb Carbon Dioxide (CO2) + Water (H2O).

The trees generally store hydrocarbons (chains in the form of CH3(CH2)nCOOH, and various other similar compounds, but mostly carbon and hydrogen).

So, I presume you are saying that they are storing 2400 – 3600 lbs of CARBON per acre, not CO2.  So, the CO2 absorbed is about 3 times the value calculated above, or somewhere around 100 gigatons on the continents (with the caveat that most is released again, as mentioned).
Title: Re: About CO2
Post by: alancalverd on 19/12/2013 00:16:26
Quote
Even the trees eventually die, and are decomposed.
which makes one wonder why coal looks like dead trees. Or indeed why Venice hasn't disappeared.

Fact is that the historic record shows very rapid rises in atmospheric CO2, each followed by a slow drift downwards. Now given the propensity of trees to grow rather slowly, the curve suggests that plant sequestration is quite a longterm effect, with a halflife of several thousand years.   
Title: Re: About CO2
Post by: yor_on on 23/12/2013 03:46:39
That's a tricky one. And myself I think it is educated guessing mostly as it seems a new field.

http://earthobservatory.nasa.gov/Newsroom/view.php?id=21354
and
http://www.enn.com/ecosystems/article/45308

And it's also about diversity, of fauna and flora. Like different types of trees sequestering CO2. Pine trees are as good a leaf trees there as I get it, but you won't see the same biodiversity. It's like using space mapping, stating that there is as much trees growing as we cut down. It doesn't tell us a thing about the biodiversity, without knowing what types of (fast growing) trees they plant, also knowing what grew (existed) there before.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 23/12/2013 17:32:04
Hardly new science. This was the substance of my first biology lesson, in 1956.

"Plants use sunlight to synthesise complex organic molecules from atmospheric carbon dioxide, with water, nitrogen compounds and trace elements principally taken up from the soil. Animals get energy from the oxidation of carbohydrates and hydrocarbons, mostly from plants."
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 26/12/2013 01:26:12
photosynthesis ain't new, but I think that discussing carbon sequestering, giving defined numbers for different environments, are rather new, to me at least.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 26/12/2013 01:44:29
I can't think why. The entire farming and forestry industries are based on quantified CO2 sequestration by photosynthesis. What the customers do with the product is another matter, of course, but if you can't calculate the mass of cabbage or construction timber you can grow in a year, you won't be able to raise capital or loans to run your agribusiness!
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 26/12/2013 02:15:42
You got a good point there Alan. It's more of looking at it another way I guess, and different trees should sequester carbon differently. Like some Forrest industry cutting down old forests with slow growing trees, having 'tight year rings', then planting other, fast growing ones, to get their new investments back as fast as possible. What that will mean in form of sequestering carbon? Maybe not as much? As they will continue to plant that variety, after thinning the woods out of grown trees again. I don't know there? It's a tricky business.
=

There is one thing though, the faster growing woods will make bad planks (bending) and so furniture, if I remember right. So there might be a higher probability that it will be used as fuel?
Title: Re: How much CO2 does a tree consume per year?
Post by: CliffordK on 26/12/2013 06:26:58
The older trees are still putting on some wood.
Consider a tree, 3" in diameter, and 10 feet tall, perhaps with 1/4" growth rings.
Vs a tree that is 4' in diameter, 12' in circumference.  100 foot tall, with 1/32" growth rings.  The big old tree may still be putting on quite a bit of wood.

Of course, you might have more little trees in a clearcut than big trees in an old growth or climax forest.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 26/12/2013 09:00:37
It's more of looking at it another way I guess, and different trees should sequester carbon differently.
I think foresters know this.
 
Quote
There is one thing though, the faster growing woods will make bad planks (bending) and so furniture, if I remember right. So there might be a higher probability that it will be used as fuel?
Again, carpenters and energy suppliers do specify their materials quite carefully. Trunk oak makes great furniture, churches and ships, but is very difficult (and expensive) to turn into fuel pellets. Birch ply is a lot stiffer than single grain softwood, so makes excellent cheap furniture and lightweight aeroplane parts. Very fast growing softwood makes adequately rigid chipboard and fibreboard, or indeed fuel.
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 26/12/2013 13:10:56
I don't think it is that simple Alan, to know how this sequestering works practically. Saw this one just now   http://www.eci.ox.ac.uk/news/articles/2013/1024plantecology.php   about 'ecosystem dynamics of Amazonian and Andean forests.' And maybe take a look at http://scitechdaily.com/shedding-light-on-the-role-of-forests-in-carbon-sequestration/   first, as it is forests we discuss.

And then we have marine biological organisms, as plankton and their shells. We also have all sorts of seaweed etc in the oceans. And it all comes together into one world interacting with itself and space. Don't think we have any perfect models for all this.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 27/12/2013 00:43:23
No need for comprehensive models. The original question was about trees consuming CO2. All the carbon in a tree comes from the atmosphere, and foresters know exactly what gain in dry weight to expect from any particular species at any stage in its development, so the answer is known. The subsidiary question of how long does that carbon remain sequestered depends entirely on what you do with the tree: anything from minutes in the case of biofuel to millions of years in the case of mined coal deposits, or for ever if you don't mine the coal.

What interests Joe Public nowadays is the re-release of plant carbon by animals. When the temperature rises, insects and other coldblooded creatures become more active and exhale CO2 derived from plant material. Hence the observed historic (and current) variation of CO2 concentration with temperature.     
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 27/12/2013 01:42:45
That may be Alan, assuming one know all parameters regarding a tree, its speed of growth, soil, sun, rain, humidity, and whatever else that may come into play? But I don't think we have those figures on a individual basis normally, outside of a lab environment? I would expect generalizations, estimates based on statistics when people discuss it. Climate science is on the whole fairly new I think, even though we understand the role of photosynthesis.
=

As for the last comment, would you have a link to what you're referring?
=

Found a description of how to calculate amount of CO2 sequestered in a tree, per year.
http://www.broward.org/NaturalResources/ClimateChange/Documents/Calculating%20CO2%20Sequestration%20by%20Trees.pdf

Now, they seem to agree with me, but then also with you :)
Title: Re: How much CO2 does a tree consume per year?
Post by: fries on 03/01/2014 22:22:43
Hi, I have a question.  I was wondering what reputable source found that mature grasslands sequester 2400-3600lb of C/acre per year?  Also, are there any sources that give estimates on other land types and their average rates of carbon sequestration per (hectare, acre, etc..) per year? 

There are lots of studies about their potential ability to store, but I am looking for what different land types sequester naturally.  I recognize the potential for variability, but was hopeful to find some roughly, average, estimated data.

Thank you
Title: Re: How much CO2 does a tree consume per year?
Post by: Bored chemist on 04/01/2014 12:24:57
Did nobody look at the numbers?
"I know 1 mature tree can store 48 lbs CO2 per year and give 260 lbs O2 per tree per year "
The big problem there is that 260 is bigger than 48.

If I said I took 48 pounds of ore and extracted 260 pounds of metal from it, would anyone take me seriously?
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 04/01/2014 14:56:24
There's a difference between turnover and surplus in any business.

Quite a lot of carbon goes into making seeds, leaves and twigs which fall off (expenditure) leaving a little to be sequestered as trunk growth (reinvested profit) and a fair quantity of oxygen (tax!). A mature private company may not worry too much about reinvestment as long as the workers, shareholders and tax man are happy with their take. 
Title: Re: How much CO2 does a tree consume per year?
Post by: Bored chemist on 04/01/2014 16:35:33
48 lbs of CO2 only contains 35 lbs of oxygen. The other 13lbs is carbon and roughly speaking that will create about 32.5 lbs of timber (calculated as cellulose).
Two things can happen to that timber. It can be incorporated into the tree, or it can be lost.
If it's lost as leaves then they decay and take up the equivalent amount of oxygen anyway.

Where does the rest of this magical O2 come from?
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 06/01/2014 04:32:24
You're perfectly correct, I definitely missed to check his numbers and taken together they make no sense to me either. I'll blame it on me being to lazy to convert it into meaningful numbers, as kg, for me. But the pdf gives a estimate in the same eh, indecipherable terminology. I now looked at lbs and found it to be a pound? 0.453592 kg.

So what he suggest is that  "1 mature tree can store 21,772416 kg CO2 per year and give 118 kg O2 per tree per year," right?

The first number seems to come from  "A single mature tree can absorb carbon dioxide at a rate of 48 lbs./year and release enough oxygen back into the atmosphere to support 2 human beings."

- McAliney, Mike. Arguments for Land Conservation: Documentation and Information Sources for Land Resources Protection, Trust for Public Land, Sacramento, CA, December, 1993

How correct that is? Depends on what tree, I would guess? and the soil, and the weather locally. Then we have using kg:s O2, instead of using liters? One kg oxygen is about 700 liter so converting it to liter that will make 118 x 700 = 82600 liter oxygen if I got it right.

And then there is the question of what a weight means here, the dry weight of a tree is what's used in the pdf and that is apparently about 72.5 times its weigh, growing in its natural 'wet' state. To get to the carbon content you multiply that dry weight (in kg:s, please) by 50% and there kg seems a good choice too.

But the first number seems plausible, the second? 82600 liter per tree, per year, right? Divide with 365 and we get... 226.3 liters per day.... (all depending on if I'm doing the conversions correctly here:). So, how much oxygen is produced by one tree, per day? I don't know really? It's a complicated question it seems. Take a look here http://wiki.answers.com/Q/How_much_oxygen_does_one_tree_produce

Ok, but how much would a average human consume per day then? That one seems possible to answer.

"Somewhere between 500-600 liters of oxygen (at 1 atm pressure) a day. That may sound like a lot, but there are only 1.42 grams of oxygen/liter at 0C, 1ATM. So that's only 710-852g/day. Or, a pound and a half to just under two pounds/day." is one answer

So assuming that the first statement is correct, and one tree is able to sustain oxygen for two persons, per year, then assuming that those use between 1000 to 1200 liters oxygen per day, then one mature tree should produce the same amount, possibly?

And I'm getting a headache :)

Arrggh.
1100 liters x 365 = 401500 liters per year.. doesn't add up to me?

(And I definitely lost myself, doing all those conversions)
==

Ok, found the other statement too.

"On average, one tree produces nearly 260 pounds of oxygen each year. Two mature trees can provide enough oxygen for a family of four." 

- Environment Canada, Canada's national environmental agency

Ah well..

Title: Re: How much CO2 does a tree consume per year?
Post by: CliffordK on 06/01/2014 06:38:00
Did nobody look at the numbers?
"I know 1 mature tree can store 48 lbs CO2 per year and give 260 lbs O2 per tree per year "
The big problem there is that 260 is bigger than 48.
See my first reply (http://www.thenakedscientists.com/forum/index.php?topic=49841.msg426991#msg426991).

I assume the author meant that the tree stores about 48 pounds of carbon.
And releases 260 lbs of oxygen. 

Don't forget that the equation is:
CO2 + H2O --> Hydrocarbons + Carbohydrates + Oxygen, however you choose to balance it.  Perhaps that is still off a bit.

But, it is about 3 oxygen atoms (AW 16) released for every carbon atom (AW 12) incorporated into pure hydrocarbons.  A bit less oxygen released for carbon incorporated into cellulose.
Hmm, with the 3:1 ratio, one still gets: 3*16*48/12 = 192    (48lbs Carbon incorporated ==> 192lbs Oxygen released).

How thick is a typical growth ring on a mature tree?  I suppose a lot of it depends on the tree.  A Douglas Fir, Juniper, or Bristlecone Pine have quite different growth characteristics.  Even the definition of a "Mature" tree is ambiguous, and would also depend on whether it is in a dense forest, or isolated.

For a "Mature" Doug Fir:
Consider 1/32" growth rings.
Let's consider a cone,
4' at the base, 100' tall. 
Surface area of a bottomless cone is
πrs, with s the length of side.
So we get about 628 square feet of new growth, or about 20 cubic feet (for 1/32" growth rings).
About 30 lbs per cubic foot density (dry?)
And, it comes up with about 600 lbs new growth a year (trunk wood). 

I suppose we're somewhere in the ballpark.

It might be a bit higher if you're calculating for a Sequoia or Redwood.  A bit less for a mature bristlecone pine or juniper tree.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 06/01/2014 08:10:03
If it's lost as leaves then they decay and take up the equivalent amount of oxygen anyway.

Not true. Most decay is anerobic (the sludge at the bottom of the leaf pile). Conversion of plant material to CO2 is mostly done by larger animals: this is called life on earth, and is the fault of god, not the tree.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 06/01/2014 08:12:07
Did nobody look at the numbers?
"I know 1 mature tree can store 48 lbs CO2 per year and give 260 lbs O2 per tree per year "
The big problem there is that 260 is bigger than 48.
See my first reply (http://www.thenakedscientists.com/forum/index.php?topic=49841.msg426991#msg426991).

I assume the author meant that the tree stores about 48 pounds of carbon.
And releases 260 lbs of oxygen. 

That is indeed what he said, and it makes perfect sense.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 06/01/2014 08:22:07
Quote
"Somewhere between 500-600 liters of oxygen (at 1 atm pressure) a day. That may sound like a lot, but there are only 1.42 grams of oxygen/liter at 0C, 1ATM. So that's only 710-852g/day. Or, a pound and a half to just under two pounds/day." is one answer

Or just over 1 kg of CO2 exhaled per day per human. Multiply by 9 x 10^9 and you find that humans contribute a massive 10 megatonnes of carbon dioxide to global warming (or is it climate change these days) every day even if they don't use fossil fuels. Shocking, isn't it? 
Title: Re: How much CO2 does a tree consume per year?
Post by: peppercorn on 06/01/2014 14:36:03
Or just over 1 kg of CO2 exhaled per day per human. Multiply by 9 x 10^9 and you find that humans contribute a massive 10 megatonnes of carbon dioxide to global warming (or is it climate change these days) every day even if they don't use fossil fuels. Shocking, isn't it? 

But this is not 'new' CO2 is it.  I'm sure that you wouldn't want to give the impression that just through respiration, humans (or any other animals for that matter) cause an inherent increase in the amount of 'free' CO2 in the atmosphere (and ecosystem as whole), would you?

Increased numbers of humans are in no way directly, by breathing, putting any more CO2 into the system. Instead, so far as 'just staying alive' goes, modern agriculture relies on unlocking fossil carbon - by using hydrocarbons to drive the Haber–Bosch process of making fertilizers.

Prior to this process becoming commercialised, there was obviously very little opportunity for stored, fossil carbon to re-enter the system. But, and this may be your pooint, there was no practical way to support the billions of people we have living on the planet today.
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 06/01/2014 15:22:33
I agree with BC that the numbers doesn't add up. But we have two separate sources saying the same here. Well, almost separate, after all, Canada and America are neighbors. The one putting those numbers into question is the one in where I found a human to use 500-600 liters per day, using that there's a big discrepancy between what a tree is expected to release compared to what we breath in and out. A tree releasing 226 liters, more or less, of oxygen, with a human consuming 5-600 liters that same day. Using that it seems to need two trees per human, per day? Could be my conversions, it was late, but, I don't think it is.
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 06/01/2014 15:44:25
The confusion seem to raise from that we can define the oxygen halt in the atmosphere, taking samples of it, all over the world on a daily basis.

"The Scripps O2 Program measures changes in atmospheric oxygen levels from air samples collected at stations around the world. This sampling network provides a global and hemispheric perspective on oxygen variability. The Scripps O2 Program is based at the Scripps Institution of Oceanography at La Jolla, California and is under the direction of Professor Ralph Keeling." http://scrippso2.ucsd.edu/

That gives us good, and reliant statistics over it. But what it doesn't, is to pinpoint what 'individuals' that create and consume it. So you can get good statistics over a large area, without being able to define each tree. Or Plankton.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 06/01/2014 16:12:50
But this is not 'new' CO2 is it.

There is very little "new" CO2 in the atmosphere. Every carbon atom in fossil fuel was previously in the atmosphere, thence absorbed by plants to make coal or via plants and animals to make oil and gas. The only "new" stuff comes from volcanoes.

Quote
I'm sure that you wouldn't want to give the impression that just through respiration, humans (or any other animals for that matter) cause an inherent increase in the amount of 'free' CO2 in the atmosphere (and ecosystem as whole), would you?
Of course they do. Remember Biology 101? Plants absorb CO2 and emit oxygen. Animals eat plants, inhale oxygen, and exhale CO2. That's life. The quantity of CO2 in the atmosphere at any time (until Mankind discovered fire) depends on the ratio of plants to animals, and it has only recently exceeded the previous peak level reached some 320,000 years ago.

Quote
Increased numbers of humans are in no way directly, by breathing, putting any more CO2 into the system.
Nonsense. Humans are animals, animals exhale CO2, so more humans = more exhaled CO2.

If you do the calculation based on the energy released by combustion of food (to produce mostly CO2 and H2O) you will find that human breathing at 10 megajoule/man.day accounts for about 10% of all anthropogenic CO2, and the animals that we farm for meat generate about 20 - 25% of the total. Furthermore, every molecule of "artificial" CO2 (from fossil fuels) is emitted to satisfy the demands of a human being, so fewer people = less CO2.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 06/01/2014 16:21:24
A tree releasing 226 liters, more or less, of oxygen, with a human consuming 5-600 liters that same day. Using that it seems to need two trees per human, per day? Could be my conversions, it was late, but, I don't think it is.

The operative phrase is "more or less". Trees come in all sizes and activities. Probably a third of the trees in the UK are quite small, deciduous, fruit trees, which only photosynthesise for about half of the year, but trees in the tropical rainforest are huge, effectively evergreen, and transpire all year round. It's noticeable that one of our transatlantic correpondents refers to sequoia as typical trees. You probably think of Nordic conifers as typical, whereas all I can see from my office are temperate beech and sycamore trees which are currently dormant and leafless.
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 06/01/2014 18:36:40
That's one way to look at it Alan. The other would then be to define it as a respiratory planet, breathing using photosynthesis, being in a equilibrium. Then came the industrial revolution, two hundred and fifty, to three hundred years ago, that now has spread all over the world, in where we dig up the stored carbon, oil, methane, etc, changing that equilibrium, introducing a ever growing excess of CO2. Methanes rest product will also be CO2.
=

Although there is more to it than that. The populations world wide has grown as I understands it, from around 700 millions in 1700 to https://en.wikipedia.org/wiki/World_population_estimates

Around 7 billions today That's 7 000 000 000 people.
It also seems as six of those 'new' billions has come to be in the last hundred years, or less.

There has to be a limit to what Earth can adapt too, and I think we're near it, in so many ways. And this time I don't think war can 'solve it' for us. It will only make it worse, like the last man standing on a (probably radioactive) garbage heap, telling himself that 'he won'. Sort of really stupid thinking that one..
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 06/01/2014 19:16:24
On the other hand. This is what a free market economy, combined with the idea that 'the market knows best' and some normal greed will lead to. The instruments for it being the modern assembly line, and automation, enabling industries to spew out products, and also to reap the benefits of raping the environment in a ever faster pace. What protects this idea is banks and corporations in where no holder of stocks really can be hold responsible for the corporations action. It limits all involved responsibilities, instead letting their personal greed, and the corporations need of profit, set what limits there might be, and so called 'ethics' :)

There are no ethics to that.
Title: Re: How much CO2 does a tree consume per year?
Post by: Bored chemist on 06/01/2014 21:58:53
Trees are mainly made of wood and water.
The water gets sucked up from the ground and doesn't make any difference to the oxygen produced.
The wood is mainly  (about 75%) carbohydrates (cellulose and hemicellulose etc).
About a quarter of it is lignin.
(from here)
http://www.ipst.gatech.edu/faculty/ragauskas_art/technical_reviews/Chemical%20Overview%20of%20Wood.pdf

Lignin also isn't a hydrocarbon (though it does have a little less oxygen pro rata than cellulose)

So, to a fairly good approximation the reaction you need is
n CO2 + n H2O --> (CH2O)n + n O2
each molecule of CO2 produces 1 molecule of oxygen
So 44 grams gives 32 grams
48 pounds gives 35 pounds

Now, does anyone have a credible answer to the question where does the other 225 pounds of oxygen comes from?
If it's from making leaves, then the tree must make a lot of them; 6.5 times more (dry weight basis) than it makes timber.
That's spectacularly inefficient.
Title: Re: How much CO2 does a tree consume per year?
Post by: CliffordK on 06/01/2014 22:12:32
So, to a fairly good approximation the reaction you need is
n CO2 + n H2O --> (CH2O)n + n O2
each molecule of CO2 produces 1 molecule of oxygen
So 44 grams gives 32 grams
48 pounds gives 35 pounds
Using your formula, if you incorporate 12 lbs of carbon, you will release 32 lbs of oxygen.
Incorporate 48 lbs of carbon, you release 128 lbs of oxygen. 

Still a little short from the original numbers.

I wonder if the OP accidentally doubled the numbers again.
128 lbs x 2 = 256 lbs.  We breathe O4 (https://en.wikipedia.org/wiki/Tetraoxygen), right?
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 06/01/2014 23:23:47
It's weird stuff :)
But interesting.

Heres another take on it. "A resting, healthy adult on an average, cool day breathes in about 53 liters of oxygen per hour. An average, resting, health adult breathes in about 500 mL of air per breath. This is called the normal tidal volume. Now, 150 mL of this air will go to non- functioning areas of the lung, called the "dead space." The average breath rate for this average person is 12 breaths per minute. So, the amount of air breathed in by the person which is available for use is 12 x (500 mL -150 mL) = 4,200 mL/minute. Multiply by 60 to get 252,000 mL/hour. That is, every hour, the person will breathe in 252 L of air. Now, on an average, cool, clear day, only 21% of that air is oxygen. So, 21% of 252 L is 53 L.

So, in an hour, the person breathes in about 53 L of oxygen." times 24? Or does this change when you sleep? It should, as well as it should change with what you are doing. But it's about the same number anyway.

Eh, not really :) The number I got here is about the same as the first one I got, but that was for two persons, per day (1000-1200 liters) Here we instead find it for one person, needing around 1200 liters oxygen per day. Or let's say a thousand to twelve hundred. It's pretty confusing. And considering that I got 82600 liter per tree, per year? Divided with 365 becoming  226.3 liters per day??

We now would need one tree to produce 1200 liters oxygen per day for one person, making the number 226 liters per day for a tree sux, real bad.

Then we come to leafs. I started with looking at plants.

"how much oxygen do plants produce in an hour. Actually, I have data for how much oxygen LEAVES produce in an hour: 5 mL. If your average plant has 30 leaves, then that would be 5 ml/leaf x 30 leaves = 150 ml/plant/hour.

So, if an average person needs 53,000 ml (53 l) of oxygen per hour, and the average plant produces 150 ml per hour, then 53,000/150 = 353 plants. Since these are round figures, let us just say that between 300 to 400 plants are needed to produce enough oxygen to keep a person alive in an hour.

Again, there are many assumptions: average leaf, average plant. Plus you will need to take into accounted oxygen production decreases as carbon dioxide concentration increases Assuming this hypothetical person is in a confined space with all these plants, the CO2 concentration will rise due to the person's expiration. This will inhibit the plant's photosynthetic rate. Oh, yes, do not forget we will need good amount of light and water, too.

wizkid"

From http://www.newton.dep.anl.gov/newton/askasci/1993/biology/bio027.htm
==

The next question could then be, how many leaves exist on a 'average leafy tree'?
I don't know?
Title: Re: How much CO2 does a tree consume per year?
Post by: CliffordK on 07/01/2014 00:13:30
I'm seeing different estimates, but the air you breathe in is about 20% oxygen.  The exhaled air is about 15% oxygen, or a difference of about 5%. 

The exhaled CO2 is about 4%.

That means your estimates are high by about 4x or 5x.

Since you don't eat trees (other than fruit)...  Perhaps one should consider how much CO2 gets converted into simple sugars and carbohydrates in fruit, vegetables, and grains (plus whole grasses consumed by livestock producing milk and meat).
Title: Re: How much CO2 does a tree consume per year?
Post by: yor_on on 07/01/2014 00:33:06
We could use the numbers Wizkid gives for defining how many leaves you would need though, assuming 5 mL, then divide that with 53000. That would give us 10600 leaves needed (per hour although in principle you can use this number for any and all hours if you get my drift).

Now, that seems possible for a tree to handle, I think? I've seen some numbers, from 30 000 up to where a mature, healthy tree might have 200,000 leaves? But I don't really know.
==

the more I look into it the more I prefer http://scrippso2.ucsd.edu/plots actually. There's so many variables involved in this, from what you do, age, condition, etc etc to how many leaves a 'average' tree might have, and as Alan pointed out, it definitely depending on where you get that 'average', from what Country and trees. Then you have seasonal changes and how much sun, soil, night activity versus the day etc. No wonder the figures seems to differ :)
Title: Re: How much CO2 does a tree consume per year?
Post by: Bored chemist on 07/01/2014 20:53:25
You could estimate the amount of oxygen someone uses in a day from how many calories they use.
(You need some information or assumptions about their diet too, but you should be able to get a ballpark figure)
 
Title: Re: How much CO2 does a tree consume per year?
Post by: CliffordK on 07/01/2014 22:16:11
Essentially all of what we eat came from plant photosynthesis in the recent past (or eating animals that ate the crops).

Having more babies means eating more crops, but it doesn't significantly impact the overall CO2 balance.

What affects the CO2 balance is digging up buried carbon, oxidizing it, and releasing it into the atmosphere, and to some extent burning wood, for example clearing rainforests to make cropland.

Of course, the more people, the more cars and energy demands.
Title: Re: How much CO2 does a tree consume per year?
Post by: alancalverd on 07/01/2014 23:27:45
The average human uses about 1.5 kilowatts of "artificial" energy, nearly all of which comes from fossil fuels. The numbers vary enormously from almost 20 kW in such diverse places as Canada and Saudi Arabia to 200W or less in parts of Africa and some Pacific islands.

The average human burns about 115 watts of food energy. Some of this comes from plants but increasingly it comes from farmed animals. We maintain about 3 times our body weight of farm animals, and all warmblooded creatures have broadly similar metabolic processes, so the animals we eat burn about  350W.

Thus about 25% of all anthropogenic carbon dioxide comes from humans and farm animals.
Title: Re: How much CO2 does a tree consume per year?
Post by: norton94 on 22/10/2014 22:15:38
My son just asked me if it would be possible to select a plant/tree based on C02 consumption and O2 emission - essentially developing a hybrid that would be more efficient at the process.  Has this been attempted?
Title: Re: How much CO2 does a tree consume per year?
Post by: Mikerc1984 on 27/05/2019 09:25:37
Great thread guys and gals.
I hope you can help point me in the right direction of research done on types of trees sequestering Carbon.
And also the best way to measure how much a tree at each year of its life has sequestered, can you measure the base and extrapolate the size then tonnage for example, then take into account the amount of water in it?
I am in need of help to show people exactly how much CO2 is sequestered when I plant a new Broadleaf woodland, and how much it will have captured over 10 20 30 years etc.
Possibly also hedgerows, and Woodland vs City trees lining roads. 
I will also be communicating with universities in the UK and looking for someone to do a thesis on this but you could help me make a start.
Regards
Michael Cunningham
Title: Re: How much CO2 does a tree consume per year?
Post by: Colin2B on 27/05/2019 22:13:41
You might start here: http://www.unm.edu/~jbrink/365/Documents/Calculating_tree_carbon.pdf
Title: Re: How much CO2 does a tree consume per year?
Post by: Rasull on 23/06/2019 09:02:21
Informative thread the above-mentioned answers are very useful, great explanation it helps me to know more about trees.
Title: Re: How much CO2 does a tree consume per year?
Post by: Jeaniecary on 13/09/2019 12:18:54
According to me it takes 48 lbs CO2 per year.