# Science/botany question **URL:** \ **Category:** Factual Questions\ **Created:** [December 25, 2000, 7:20pm UTC](https://boards.straightdope.com/t/science-botany-question/47183 "2000-12-25T19:20:13Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![McMurphy](https://avatars.discourse-cdn.com/v4/letter/m/e19adc/32.png) [@McMurphy](https://boards.straightdope.com/u/McMurphy)\ **Post date:** [December 25, 2000, 7:20pm UTC](https://boards.straightdope.com/t/science-botany-question/47183/1 "2000-12-25T19:20:13Z")
As I understand it plants use a chemical process called photosynthesis to convert carbon dioxide to oxygen which then then “breathe out” so to speak. My question is, is it possibleto measure how much oxygen a plant can produce? For example if you had an average sized tree with an average amount of leaves in good condition, would it be possible to measure how much oxygen the tree exudes and if so, what is the exact proceedure used? Thanks ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [December 26, 2000, 12:14am UTC](https://boards.straightdope.com/t/science-botany-question/47183/2 "2000-12-26T00:14:46Z")
Put “measure tree oxygen output” into Google and get, among other hits, [http://www.newcastle.edu.au/kooragang/mr\_treevalue.html](http://www.newcastle.edu.au/kooragang/mr_treevalue.html) That’s as much as I can do for you right now, 'cause I don’t have a CLUE as to what a “mole” is, other than an underground tunnel digger and lawn nuisance. 😃 ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [December 26, 2000, 12:54am UTC](https://boards.straightdope.com/t/science-botany-question/47183/3 "2000-12-26T00:54:18Z")
> **[Dictionary.com Is The World’s Favorite Online Dictionary](https://www.dictionary.com/)** > > Dictionary.com is the world’s leading online source for English definitions, pronunciations, word origins, idioms, Word of the Day, and more. The amount of a substance that contains as many atoms, molecules, ions, or other elementary units as the number of atoms in 0.012 kilogram of carbon 12. The number is 6.0225 × 1023, or Avogadro’s number. Also called gram molecule. The mass in grams of this amount of a substance, numerically equal to the molecular weight of the substance. Also called gram-molecular weight. See Table at measurement. ---
**Author:** ![Gaspode](https://avatars.discourse-cdn.com/v4/letter/g/aeb1de/32.png) [@Gaspode](https://boards.straightdope.com/u/Gaspode)\ **Post date:** [December 26, 2000, 1:10am UTC](https://boards.straightdope.com/t/science-botany-question/47183/4 "2000-12-26T01:10:45Z")
There have been some studies done in which trees have been put in airtight tents or buildings, and the total amount of oxygen in the atmosphere carefully measured going in and out. This is the only way to measure exactly how much oxygen a tree produces, and is a little dodgy because the tree can’t be directly exposed to natural climatic conditions or even unfiltered sunlight. The more common process is simply to measure how much oxygen is produced in a given time period by a range of individual leaves on a tree, again by wrappiing them in glass or clear plastic. From this you can calculate the average amount of oxygen produced per square centimetre of leaf area, and over a range of environmental conditions. By stripping the tree and weighing all the leaves you can then get a fairly accurate estimate of the total leaf area of the tree, and this can then be applied to other trees of the same species. The other point to remember is that plants also burn oxygen, and it is neccesary to calculate the amount of oxygen the tree is consuming if you want an accurate estimate of a plants total oxygen production. By and large only growing plants are net oxygen producers. Mature trees produce and consume about the same amount of oxygen in any given year. ---
**Author:** ![Sue\_Jo](https://avatars.discourse-cdn.com/v4/letter/s/8797f3/32.png) [@Sue\_Jo](https://boards.straightdope.com/u/Sue_Jo)\ **Post date:** [December 26, 2000, 1:21am UTC](https://boards.straightdope.com/t/science-botany-question/47183/5 "2000-12-26T01:21:50Z")
I get pamplets all the time on how much oxygen trees put out, but it’s always measured by the kiloacre or something improbable. I just have to say Let’s plant more trees where there are cars, around every parking lot. and let it go at that.