| [College of ACES] | [University of Illinois] | [Illinois CES] |
I am truly sorry if I have caused you any discomfort. As it was never my intention to ridicule.
I have little doubt of your skills and valuable insights.
The responses made in the effort of helping those asking for help are many times Given in a spare moment and as always the requests lack sufficient detail and leave us guessing at a host of possible influences. As we know we could talk of circumstances all day on the phone but the field inspection leaves open a whole new set of changing perspectives. I suppose that is what has drawn me to Arboriculture. The desire to take into account all that is in concern. What could be more challenging then An endless search for an ever greater understanding.
Did you ever find out how much Euc weighs by the cu. ft. or cord? My estimate of 50 lbs has no respectable merit for belief.
Do you have any of Don Blair's books. He responded
Thanks for the info. I published a more detailed Green Log Weight Chart in my
catalog in 1986 and reproduced it in my 1995 ISA book, Arborist Equipment.
It is a very useful guide in appreciating the weight of big wood.
Thanks for thinking of me. Take care and keep in touch.
Don Blair
I had attended a presentation he gave once about 5 years ago in Miami. He's full of ideas.
I suppose when I get a chance to I will get his books to add to a growing library.
----------
<i>> I first arrived at 60,000 pounds for the log. But then I thought too hard and mistakenly used the 2,000 pound per ton figure, instead of the 6,000 pound per cord of Euc figure I intended. Sharp of you to catch this error.</i>
<i>> </i>
<i>> Try this calculation on for size:</i>
<i>> </i>
<i>> Average the log (6' + 12' divided by 2) out to a cylinder 9 feet in diameter.</i>
I can't quiet put my finger on it but the part about dividing by two bothers me a little. A haunting realization keeps coming to mind. I divised a method for bidding tree removals that hinges upon establishing a relation between tree diameter at breast height and the volume of above ground mass a tree possesses. In dealing with formulas in developing volumes for round objects pie 3.14 is used extensively. For instance I think that the volume of a 1 foot dbh tree isn't 1/2 as much as the volume in a 2 foot dbh log. I am suspicious that the volume of the 2 foot log is 3.14 times greater than the 1 foot dbh log. For simplicity lets give the log a length of 10 feet.
and for simplicity again lets say the log is also the same dimension on both ends so we can use the cylinder formula you mentioned below.
<i>> Use the Pi X Radius squared X Length formula for cubic volume of a cylinder.</i>
Volume for 1' X 10' cylinder = 3.14 X (.5 X .5) X 10 = 3.14 X .25 X 10 = 7.85
Volume for 2' X 10' cylinder = 3.14 X (1 X 1) X 10 = 3.14 X 1.0 X 10 = 31.4
7.85 divided into 31.4 = 4 This doesn't seem right does it. I wonder if its the fraction I used.
I'll try it again but use inches instead so their won't be any fractions involved.
Volume of 12" X 120" cylinder = 3.14 X (6 X 6) X 120 = 3.14 X 36 X 120 = 13,564.8
Volume of 24" X 120" cylinder = 3.14 X (12 X 12) X 120 = 3.14 X 144 X 120 = 54,259.2
13,564.8 divided into 54,259.2 = 4 WOW!!!!! its still the same.
I always thought a 12" log was 1/3 of a 24" log. Not 1/4
Below is your estimate for a log 12' big end 40' long and 6' small end. Is this right?
<i>> Average the log (6' + 12' divided by 2) out to a cylinder 9 feet in diameter.</i>
<i>> Use the Pi X Radius squared X Length formula for cubic volume of a cylinder.</i>
<i>> 4.5' X 4.5' = 20.25 X 3.14 = 63.585 Sq. ft. X 40' = 2,543 Cubic feet</i>
2,543 divided by 128 cu ft. per cord = 19.87 cords
<i>> </i>
<i>> 20 cords times 6,000 lbs per cord = 120,000 lbs = 60 tons</i>
According to my figure using the Frustum formula the log we started with 12' big end 40 ft length and 6' small end, should have only 791.6832 cu. ft divided by 128 = 6.185025 cords.
I am a little confused as to how we could be so different in
yours = 2,543 divided by 128 cu ft. per cord = 19.87 cords
mine = 791.68 divided by 128 cu. ft. per cord = 6.18 cords.
That is a whopping big difference don't you think?
I checked mine and yours to see if one of us made an error but I can't see any mistakes in the math or the formulas we used. Do you see something I missed.
Of course we are using different formulas but both are validated.
I wonder if the difference may be derived in the one thing thats not a standard formula that you used in developing a average size.
namely > Average the log (6' + 12' divided by 2) out to a cylinder 9 feet in diameter.
It sounds good to me too but maybe there is something in it we don't quite understand.
For your reference I have included my previous used Frustum formula.
Formula = The volume of the frustum of a cone is equal to the sum of the squares of the diameters of the bases, plus the product of the diameters of the bases with this sum multiplied by .2618 times the altitude.
Formula
You will need to substitute in the figures for the letters.
V = volume of log
D = big diameter end of log
d = small diameter end of log
H = Height or distance between ends of log
V = .2618H ( D2 + d2 + Dd ) = .2618 @ H @ ( D2 + d2 + Dd )
D = 12 = foot diameter on big end
d = 6 = foot diameter on small end
H = 40 = height or distance between ends
V = .2618 by 12 ( 12 to 2nd power + 6 to 2nd power +12 by 6 )
V= .2618 by 12 by ( 12 to 2nd power + 6 to 2nd power + 12 by 6 )
V = 3.1416 (144 + 36 + 72)
V = 3.1416 by 252
V = 791.6832 cu. feet
If the logs volume is 791.6832 cu feet and there are 128 cu feet in a cord than 791.6832 divided by 128 should equal how many cords are in the log.
791.6832 divided by 128 = 6.185025 cords.
<i>> </i>
<i>> A few observations: My view of a cord includes 15% air space. The bark also would weigh less than the wood for even more slop (I like slop). This could give a solid chunk of log, say, 20% more weight than split & stacked firewood. </i>
I would suspicion that air spaces weren't figured in the formula or in the cu. ft. weight.
The application is a little different than actual stacks I think and doesn't have any bearing on the weight of the log. However the bark sure would make a difference I would think. I wonder if that chunk of wood were heart wood would it weigh different than sapwood and or bark. Leaves me to wonder if in the shear greater volume of log that the proportions of these might change the overall weight averages.
<i>> </i>
<i>> After using a calculator, it is apparent that a 4 1/2 foot log 8 feet long equals a cord. For slop's sake, we can still call a 4 footer a cord.</i>
Using the cylinder formula
<i>> Use the Pi X Radius squared X Length formula for cubic volume of a cylinder</i>
volume 3.14 X (2.25 X 2.25 = 5.0625) X 8
=(3.14 X 5.0625 = 15.89625 )X 8
= 15.89625 X 8
=127.17
Thats close enough to a cord for me any day.
<i>> </i>
<i>> I had no idea Live Oak weighs 9,000 pounds per cord, Euc is probably 7-8.</i>
<i>> Here is a web site that does conversions automatically: <a href="http://www.mplik.ru/~sg/transl/capacity.html">http://www.mplik.ru/~sg/transl/capacity.html</a> Typing in 128 cubic feet, the result shows about 100 bushels as the equivalent. Not much good for cordwood.</i>
<i>> </i>
<i>> An old tree appraisal computer program by Kim Coder gives wood volume in cord units. Have you seen it?</i>
No I haven't ever seen it?
I am still very concerned as to our different estimations.
Go Figure!
"The Corridor" H.A.T.S. Highspeed Automated Transport System
Mans economical opportunity for ecological and social enhancement
Act Locally
Think Globally
George <a href="/cgi-bin/mail?to=schrader@beaches.net&replyto=9703112342.AA04784@spectre.ag.uiuc.edu&subject=Re:%20Re:%20Analyzing%20tree%20weight%20formulas">schrader@beaches.net</a>
American Tree
1309 W. 10th St.
Panama City, Fl 32401
Tel 904 769 4060
Portable 904 832 0274
Pager 1 800 849 6162