The atmosphere of the Earth has a different composition from that of other planets in part due to the biochemical reactions of Earth's organisms. Trees and plankton play a big role in this. You've probably heard that trees produce oxygen, but have you ever wondered how much oxygen that is? You'll hear a range of numbers and ways of presenting them because the amount of oxygen produced by a tree depends on the species of tree, its age, its health, and also on the tree's surroundings. According to the Arbor Day Foundation, "a mature leafy tree produces as much oxygen in a season as 10 people inhale in a year." Here are some other quoted figures regarding the amount of oxygen produced by a tree:
"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
"One acre of trees annually consumes the amount of carbon dioxide equivalent to that produced by driving an average car for 26,000 miles. That same acre of trees also produces enough oxygen for 18 people to breathe for a year."
- New York Times
" A 100-ft tree, 18" diameter at its base, produces 6,000 pounds of oxygen."
- Northwest Territories Forest Management
"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
"Mean net annual oxygen production (after accounting for decomposition) per hectare of trees (100% tree canopy) offsets oxygen consumption of 19 people per year (eight people per acre of tree cover), but ranges from nine people per hectare of canopy cover (four people/ac cover) in Minneapolis, Minnesota, to 28 people/ha cover (12 people/ac cover) in Calgary, Alberta."
- U.S. Forest Service and International Society of Arboriculture joint publication
Comments
I don’t want to sound rude, but your calculations are either meant to be missleading or you have no clue what you are talking about.
” A 100-ft tree, 18″ diameter at its base, produces 6,000 pounds of oxygen.”
I’m assuming that is true. But that same tree will also consume (get rid of) 8251.875 (8000 to significant figures) pounds of carbon dioxide. The Math at the end.
An average human consumes 550 liters of oxygen daily, which is 631 lbs a year, (density of oxygen is 1.46 g per liter), so that same tree could support almost 10 people, not two.
Basically that one 100 ft tree would consume 1.33 pounds of CO2 for every 1 pound of oxygen it creates, and will support 10 people yearly.
“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.”
Must be a tree the size of a peace of paper. That same tree would produce much less oxygen. and would support less than one person a year.
6000 lbs of O/2.2 (convert to kilograms), *1000 (convert to grams) / 32 (convert to moles of oxygen) (in the photosynthesis reaction that trees do to create energy but also oxygen, the balanced equation is 6CO2+6H2O–>C6H12O6+6O2) so for every mole of oxygen there is one mole of carbon dioxide, so take the answer from before (85227.27 mol O) convert it to mols CO2, (which is the same number) times by molar mass of CO2: 44.01g, divide 1000 (to convert to kilograms of CO2) times by 2.2 (convert answer into pounds) = 8251.875 pounds of Carbon Dioxide per year. Because the original number being worked with was 6000, which is only 1 significant figure, only one carries over, so 8251 becomes 8000.
Theres the math, kind of confusing written like that, but thats the best I can do with typing in a text box.
What???! Your opening statement: “I don’t want to sound rude, but your calculations are either meant to be missleading or you have no clue what you are talking about.”
The author has not made claims, but quoted other well respected authorities. You should know that!
You don’t want to sound rude? You couldn’t sound more rude if you tried and you are not even aware of it? It throws all your claims of logic into doubt from the first base.
A very interesting article and worthy of ‘adult’ discussion.
If you notice she actually just found information from other sources and quoted it because her first quote from Arbor Day Foundation states exactly what you said 1 healthy tree can produce oxygen for 10 people for a year. My whole grip is why don’t people see all these figures that are great ones instead of just all the bad. Work something out with the good instead of complaining about all the bad in the world. Great information everyone.
“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
Using the same formulat above, that ‘average tree would consume 360 pounds of carbon dioxide each year. You would need 3 of those trees to support one person. It would not support two by itself like you said.
” A 100-ft tree, 18″ diameter at its base, produces 6,000 pounds of oxygen.”
Say that a collection of those trees filled one entire hectare with 100% canopy cover, I’m assuming that the canopy if viewed as a circle will have a diameter of about 20 feet. so the area that covers is pi*10^2= 314.159 square feet which is equal to 29.20 meters squared. 1 hectare is equal to 10000 square meters so, one hectare would have aproximately 342 of these trees (10000/29.2). As mentioned above, one of those trees produces 6000 lbs of oxygen, so 342 times 6000= 2052000 pounds of oxygen. One human needs about 631.5 pounds of oxygen a year (mentioned in last comment) so 2052000/631.5. Thats 3249 people, not 19. Now unless im missing something really big, this article is complete bs. I’m srry, please correct me if I’m wrong, im ready to learn.
Dr. henry i’m not a talanted person like you but i think i would like to ask to you that if a tree produces the oxygen nearly about 6000 pounds of oxygen. Very large portion of it is used by plant during respiration so the actual production is much more less than expected. It’s only my thought not the finding of the research. I could be wrong too.
Now I believe the real question is not how much CO2 the tree absorbs but how much O2 it produces. Do the math again and try to make it a little more simple Dr. Henry, a human consumes approximately 6-8 lbs of oxygen a day ( right now I’m going to meet it in the middle at 7), so 7*365=2555 per year. Now, I’m not an expert on trees but if a 100-ft tree 18″ at the base produces about 6000 lbs every year, it would be able to produce enough oxygen to support 2.34833659 …. people.
Great display of figures and math, and I appreciate it.
If someone wants to account for the approx amount of trees on Earth, please don’t forget to add in the other beings that share the Earth with humans, i.e. animals, insects, germs.
Even the weather relies on air and its density thereof.
Umm I think we are all a bit on a hit and miss here. You all keep converting to Pounds and liters and so on which id baffling bc you are making a lot of assumptions (which is bad). when dealing with an ideal gas under standard conditions it goes PV=nRT (pressure x volume=# of moles x gas constant x temp) but seeing as how our surroundings are NOT standard then these converstions are pointless. When doing the math just keep it simple and stick with like units.
Joe, double check your units.
The average person consumes between 6-8 LITERS of O2, not pounds. if you make the conversion yourself using dr henry’s formula supplied above, you’ll get the correct figures…
Source
http://health.howstuffworks.com/human-body/systems/respiratory/question98.htm