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How many trees make a cord

Discussion in 'Firewood, Heating and Wood Burning Equipment' started by steviep, May 21, 2008.

  1. steviep

    steviep ArboristSite Lurker

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    I am planning to cut down some trees this weekend. Most are 8 inch or larger and at least twenty foot before you get to the branches. Just trying to figure how many trees i need to get 7 to 10 cords.
     
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  2. Stihl051master

    Stihl051master ArboristSite Operative

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    You'd just have to figure the volume of each log. A cord is 128 cubic feet. The formula for volume is pi(about 3.14159) x radius squared x length ( do all measurements in feet). For example, if you had a 12" round log that was 20 ft long, it would work out to just under 63 cubic feet. So, if you wanted 10 full cords, you'd need a bit over 20 logs. 7 full cords would be a bit over 14. Hope this helps!
     
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  3. turnkey4099

    turnkey4099 Tree Freak

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    Errmmm...not quite right. A cord is defined as a 'tightly stacked' pile that contains 128 cu ft, 4x4x8 for example. But that 128 cu ft contains a lot of air space no matter how tightly stacked. Thus you sample above will stack (tightly) to considerably more than 63 cu ft.

    Harry K
     
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  4. mga

    mga Tree Freak

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    i think you'll be cutting up alot of them to get a full cord.

    trees look big when they're standing there, and when cutting they seem to get bigger...lol.... but, once split and stacked, they sure seem to shrink.
     
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  5. Engineeredlawns

    Engineeredlawns ArboristSite Lurker

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    Not exactly correct. The radius is the measurement from the middle of the circle to the outside. THe diameter is the measurement from outside to outside. Logs are measured by diameter. Here is a chart I did to get the volume per ft of log.

    Diameter Volume Ft Length for a cord
    8 0.35 286.62
    10 0.55 183.44
    12 0.79 127.39
    14 1.07 93.59
    16 1.40 71.66
    18 1.77 56.62
    20 2.18 45.86
    24 3.14 31.85
    26 3.69 27.14
    28 4.27 23.40
    30 4.91 20.38
    36 7.07 14.15

    I figured the lenghts using 100 cf for a cord due to the fact that split wood stacked has some space. 67 CF may be a better figure. What ever you want to use, say 67 cf, devided that by the volume per foot to get the lenght needed. 12" log 67 cf stacked for a cord 67/.79=84.8 feet needed for a cord.

    Hope this helps
     
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  6. Nuzzy

    Nuzzy Trail Gnome

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    Stihl051 is correct on how to find volume. Pi x r^2 x length

    Yes logs are usually measured in diameter but in order to calculate volume, you must use the radius (half the diameter).

    However, it is true that a cord (the way it's written) takes into effect airspace in a tightly stacked pile of wood.
     
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  7. darren_nh

    darren_nh ArboristSite Operative

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    I have read in a few places that a tree with an 18" DIAMETER trunk cut (including tops and such) yields about a cord of firewood. I have yet to test this myself, but seems about right.
     
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  8. ropensaddle

    ropensaddle Feel Lucky

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    So how many cords is in a tree with five cords of limb wood?
    I cut a very large make that huge oak that was killed in a lightning
    strike the owner saved all wood down to five inch diam and the tree had five full cords of limbwood. I was not there to see what the 56" dbh trunk netted so I am guessing another two so a seven cord tree!
     
    Last edited: May 22, 2008
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  9. Booshcat

    Booshcat ArboristSite Operative

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    This is a grapple load that was sold as 7 Cord....
    The guy actually said he threw on some extra for me.

    Looks like a lot of wood on the truck

    When dumped on the ground it sure looks like less

    I guess I wont know till It's all split.

    Oh yeah, I paid $85 a cord or $595

    I'm hoping it's two years worth for me.
     
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  10. blackdogon57

    blackdogon57 Addicted to ArboristSite

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    Grapple Load

    I buy a lot of firewood logs for processing and resale and it looks to me that that load is not close to 7 cords. You should count on around 6 cords for a properly packed single grapple load. Tough to tell from a couple of pictures but that load does not look to be well packed on the truck and has several bent logs that create air space on the load. The grapple also takes up a lot of space on top of the load. There are also several logs that look like they are punky in the middle. If I had to make a best guess based on what it looks like on the ground I would say you have around 5 to 5.5 cords. Please post actual amount when you cut split and measure.

    Good luck !
     
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  11. flewism

    flewism ArboristSite Operative

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    This spring I dropped a 22" shagbark hickory that I computed was about 48' tall with 14' of straight trunk. I got just over 1 1/2 full cords out of it total cutting everything 3" and larger. 3 years ago I bought 2 "grapple loads" of ash for $150 each and I got about 4.5 full cords out of each pile. I didn't see the wood on the truck , just a pile of logs when I got home from work. I now wish I'd bought 10 loads then as they only did that for that one year at that price.
     
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  12. Stihl051master

    Stihl051master ArboristSite Operative

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    Whoops! When I figured the volume for the 12" round it should have been about 15.7 cubic feet (hey it was late). I gave the volume for a 24" round 20' long at 63 cubic feet. At any rate the guys are right that a cord of wood is 128 cubic feet tightly stacked, so with the airspace you would get always get more wood no matter how tightly you stacked it. I just figured this way if you needed a minimum amount you wouldn't "cut yourself short".... It's just a rough idea anyway, trees don't often grow perfectly round and the same diameter from ground to top.
     
  13. darren_nh

    darren_nh ArboristSite Operative

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    That looks to be a small grapple load. I received mine on Monday and is at least half again larger. Theguy isn't doing you any favors by dumping is right on the ground. Next time ask him to place a couple of transverse logs on the ground before offloading the truck so the entire pile isn't sitting on the ground. I typically request nothing over 16" in diameter as I don't want to lift large rounds onto the splitter if I can help it.
     
  14. Husky137

    Husky137 Addicted to ArboristSite

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    It looks like less because it is. A lot of junk in there too. You got screwed.
     
  15. BlackCatBone

    BlackCatBone AboristSite Guru

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    How about this then: Pi/4 * D^2
     
  16. Nuzzy

    Nuzzy Trail Gnome

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    Still need to factor in length :D:D

    Good math though. Took me a second to wrap my mind around it :greenchainsaw: :laugh:
     
  17. acer saccharum

    acer saccharum ArboristSite Member

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    You can think of it this way for a quick estimate.

    If your log could be a perfect 8" diameter end to end. (which obviously is not the case.)
    Make a row of 6 logs side by side and your row is 4 feet wide.
    Stack 6 of those rows on top of each other to get 4 feet high.
    36 logs total.
    So if they are 8' long you have a cord. Obviously after cutting and splitting it will stack up differently.

    Same logic on 10" logs, 5 side by side = 50" which is close to 4', so you will need 25 10" logs 8 feet long are about a cord.

    12" logs, 4 make 4', so your pile needs to be 4x4 or 16 8' logs.
     
  18. ray benson

    ray benson Tree Freak

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  19. Firewolf

    Firewolf ArboristSite Lurker

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    I think you might have maybe 4 1/2 to 5 cords not 7
    Big stuff it could be better but the price is right?
     
  20. Tazman1602

    Tazman1602 ArboristSite Operative

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    Man I don't know. That looks a bit shy of 7 cords to me. I just got this ten cord load for $750.
     

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