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Log Weights

Discussion in 'Stickies' started by DDM, Sep 27, 2006.

  1. DDM

    DDM Addicted to ArboristSite

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    Last edited by a moderator: Jun 1, 2008
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  2. LightningLoader

    LightningLoader ArboristSite Operative

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    interesting....
     
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  3. ddhlakebound

    ddhlakebound Addicted to ArboristSite

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    Interesting and handy.....gonna print out a copy to keep in the truck.

    On the Dept. of the Interior "Weight of Green Logs" chart, at the top, it says weight per linear foot, I believe that should be weight per cubic foot.
     
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  4. John Paul Sanborn

    John Paul Sanborn Above average climber

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    No it's the weight of a cylindar which uses the cuft weight (w) in the formula

    (Pi r squared) * h)* w

    So the column under that heading is the value for (w), where the row on the top is the value for (d) which you divide by 2 to get (r)

    On small logs you can use 3 for Pi, but 3.141 is better in bigger ones, or you can be off hundreds of pounds.

    3.141592653589793238462643383279502884197169399375 would be overkill :laugh:

    I've memorized 3.141592 just to one up my Dad.
     
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  5. M.D. Vaden

    M.D. Vaden Addicted to ArboristSite

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    Well, it may not be a piece of cake, but you've got a piece of pie... :rockn:
     
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  6. ddhlakebound

    ddhlakebound Addicted to ArboristSite

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    JPS, I understand what you are saying (all except "cuft weight"), but I don't think you saw the column I was referring to.

    The far left column, directly right of the "species" columm is headed "weight per linear foot". This is the column I believe should be headed "weight per cubic foot".

    All the other columns are the listed weight for a one foot section/cylinder of a certain average diameter.

    The math above is the long way of taking the weight of avg. diameter x length in feet to approximate the weight of the log.

    But the math above does not get you all the way there......here's an example:


    Lets use a shagbark hickory log, twelve feet long, 24 inches diameter at the base, 20 inches at the small end, call the average 22 inches diameter.

    using pieR2 to get the square inches of the log, and multiplying by the length to get the volume, in cubic inches

    radius 11 inches, squared = 121 x 3.14159 = 380.13 square inches, times the length, 12 feet or 144 inches = 54738.72 cubic inches.

    Now convert to cubic feet, one cubic foot = 1728 cubic inches, so our log holds about 31.7 cubic feet of wood. Listed at 64 pounds/foot3, the log should weigh about 2028 pounds.

    Now lets cross check:

    The chart lists shagbark hickory of 22 inch diameter one foot long weighing 169 pounds. Multiply by 12, and the log weighs........2028 pounds.

    I've never seen "linear" used to describe mass, volume, or weight.......

    Still think the "linear weight" column header is right?

    edited to change left to right in second paragraph.
     
    Last edited: Sep 27, 2006
  7. buzz sawyer

    buzz sawyer Addicted to ArboristSite

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    ddhlakebound, I believe you are correct. The first column should be weight per cubic foot. If it were weight per linear foot, it would have to be for a particular diameter since only one weight is stated. The columns at the right give the weight per linear foot - based on avg diameter. At first I thought the weights were a little high but then I saw this is weight for green wood. There was another chart showing approximate btu's for different woods that included wgt per cubic foot but I can't find it.

    I had seen this chart before but missed this. Good catch!
     
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  8. Ekka

    Ekka Diploma Horticulture + Diploma Arboriculture (Leve

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    I think the woodweb link is for dried log ...

    ,,,, the Sherril one wont open for me, some sort of error??!!

    Good one DDM, got any others, or can some-one maybe save the Sherril one then post it here that way I'm not trying to download from their server.
     
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  9. xtremetrees

    xtremetrees Banned

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    They dont upload kangaroo Ekka your to far away from us.
    What a handy chart I always wondered what the crane man was a reading. Simple go right into my truck for all to see. Ty much DDM
     
  10. buzz sawyer

    buzz sawyer Addicted to ArboristSite

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    Ekka, I was able to open it once. After closing it, I had to reboot to open it again. I may have an old version of Adobe. Tried this repeatedly with same results, even with the copy I saved some time ago. I'm going to try for a newer version of Adobe.
     
  11. DDM

    DDM Addicted to ArboristSite

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    Hmmmmm

    [​IMG]
     
  12. buzz sawyer

    buzz sawyer Addicted to ArboristSite

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    Aha - very wise, David!
     
  13. John Paul Sanborn

    John Paul Sanborn Above average climber

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    You are correct sir, that column should be per cu ft (cubic foot) I habitually drop the space

    From Wikipidia
    Symbols

    There is no universally agreed symbol but the following are used:

    * cubic feet, cubic foot, cubic ft
    * cu ft, cu feet, cu foot
    * ft³, feet³, foot³
    o feet^3, foot^3, ft^3
    o feet/-3, foot/-3, ft/-3
     
  14. jefflovstrom

    jefflovstrom Not working at Mc Donalds.

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    Dude, It is because you are thinking when you was younger, now you are working when you are older.
    Jeff Lovstrom
     
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  15. younggun

    younggun ArboristSite Operative

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    any one notice the chart and the calculator give different estimates for the same peace of wood?

    basswood,36",1' section
    calculator:248 lbs
    chart:297 lbs
     
    Last edited: Oct 1, 2006
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  16. Tree Machine

    Tree Machine Addicted to ArboristSite

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    The weight charts are informative, but they could be more useful with some further number crunching and layout.

    For instance, a commercial treeguy who produces commercial firewood doesn't really much care how much a 12" (30.5 cm) length of wood weighs because he's shooting for 16" (40.6 cm) Twelve inches would be an oddball size.

    Smaller diameters, weight is never really considered when bucking firewood. Its the bigger diameters that weight becomes an increasingly bigger issue. A 16" block of 16" diameter hardwood weighs what? A 24" (61 cm) diameter firewood-length block weighs what? The biggest tree diameter the pro-bucker would likely get into would be, say 4 feet (122 cm), so what does a 16" cookie, 4 feet across weigh. This matters, as the round often needs to be either lifted onto a truck, or rolled up an incline.

    For commercial firewood makers, a chart of the species, offering the weights in standard firewood length would be interesting to know. The loaders could guess the weight of the round, then check their guesses against the chart, keep the mood light during the heavy lifting.
     
  17. ironpig70

    ironpig70 ArboristSite Member

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    well i have a 48" +/- white oak and i'll be cutting 18" rounds off it then splitting it. after seeing this chart i'm not looking forward to man handling a vw bug:hmm3grin2orange:
     
  18. ddhlakebound

    ddhlakebound Addicted to ArboristSite

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    Yikes!!! That will be some heavy lifting indeed. Calculating at 62 lbs/cu ft, for white oak, a 48 inch diameter disk, 18 inches long, will hold 18.8 cu ft of wood, and weigh 1169 pounds.

    To be well laid out and comprehensive, you would almost need a weight table for each species, or lump species together which fall into a certain weight range per cubic foot.

    Anybody think this would be handy enough to want more tables, or is it easier to just do the calculations off the lbs/cu ft weight?
     
  19. John Paul Sanborn

    John Paul Sanborn Above average climber

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    I think taking the tables and making 3-4 groups would suffice.

    I allways tought it would be nice to have a slip card weight per dia/ft (or woould dia:ft be more acurate?)

    Hvae it on a lanyard gromit and you can get an accurate estimate by d=taping the log.

    If anyone remembers the crazy man from Oz who does euk removals with det cord, he has a book of tables and D-tape on his belt for calculating loads in the tree. It's in one of his vids.
     
  20. Tree Machine

    Tree Machine Addicted to ArboristSite

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    and diameter per 16" firewood-length as one of the columns.

    How bout a digital tape measure? They make em for carpentry and construction. Ours would need to calculate weights based on LxD x specie factor, calculate distances, act as a protractor to give us angles and have a green laser built into it. Modern day's answer to a cruising stick.
     

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