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Could Deforistation lead to lack of ability to light fires?

  1. Dec 10, 2003 #1
    The rainforest produces a good amount of o2 (exactly how much I'm not sure), could deforistation of the rainforest lead to such a decrease of o2 in the air that fires wouldn't be able to light? About how much could the percent of o2 in the air vary before fires stopped being able to burn?
     
  2. jcsd
  3. Dec 11, 2003 #2
    Most oxygen in the air is produced by algae, not rainforests. If all of the oxygen production in the world was stopped, and the remaining oxygen was completely consumed, then sure forest fires wouldn't be able to light. But then again we'd all be dead. Trees included.
     
  4. Dec 11, 2003 #3

    ShawnD

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    Don't trees consume as much oxygen at night as they produce during the day? I heard something like that somewhere....might have been TV.
     
  5. Dec 11, 2003 #4
    Yes, algae produces about 70% of the worlds o2 and the rainforests produce about 20%. I'm not saying eliminating all the o2, but if let's say, the current amount of o2 in the air (about 21% or so, right?) was reduced to something like 19%, humans would, as a whole, be fine.

    Bassically what I'm asking is: what percent of the air does o2 need to make up for fires to burn?
     
  6. Dec 11, 2003 #5

    ShawnD

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    Depends entirely on air flow. If you have massive amounts of air flow, you can have a roaring fire with very low concentrations of O2. If you have poor air flow, higher concentration of O2 in the air is needed.
     
  7. Dec 11, 2003 #6
    what about in your house, with presumably no airflow or very little, perhaps that caused by central air, a fan or a draft.
     
  8. Dec 11, 2003 #7

    chroot

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    We need about 0.16 atmospheres partial pressure of oxygen to remain conscious.

    - Warren
     
  9. Dec 11, 2003 #8
    Care to put that in terms of percent, or does that bassically mean 16%?
     
  10. Dec 11, 2003 #9

    chroot

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    You can't just express it in percent -- it depends on the pressure. For example, at 1 atmosphere of total pressure, here on the surface of earth, I need a 16% fraction of 02 to stay conscious.

    If I dive to 33 feet in seawater, I am exposed to 2 atmospheres of pressure. There, I can survive with only an 8% fraction of 02.

    - Warren
     
  11. Dec 11, 2003 #10

    ShawnD

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    16% assuming that the air pressure is at 1 atm.
     
  12. Dec 11, 2003 #11
    Alright, I understand that, so bassically if all the rainforests were completely destroyed without any other loss of vegetation we could just remain concious
     
  13. Dec 11, 2003 #12

    chroot

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    Or we could pressurize our living environments.

    - Warren
     
  14. Dec 11, 2003 #13
    By doing what, living in underwater colonies, building domes around cities?

    Do you happen to know the atmospheres partial pressure needed to light a fire?
     
  15. Dec 11, 2003 #14

    chroot

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    Depends on the fuel.

    - Warren
     
  16. Dec 13, 2003 #15
    the fuel being oxygen in the air, or did you mean like wood/oil?
     
  17. Dec 13, 2003 #16

    chroot

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    The oxygen is (not suprisingly) the oxidizer. The fuel is the wood, oil, or other substance which is oxidized by the oxidizer.

    - Warren
     
  18. Dec 13, 2003 #17
    Well how much difference is there between different sources of feul, for instance, wood and oil.
     
  19. Dec 13, 2003 #18

    chroot

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    A huge difference.

    - Warren
     
  20. Dec 13, 2003 #19
    So how much atmospheres partial pressure do you need to sustain a wood fire and an oil fire?
     
  21. Dec 14, 2003 #20

    ShawnD

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    Why do you thik he would know that? It's not exactly common knowledge.
     
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