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question about how much firewood in tops of trees

Started by letsgetitracing, January 04, 2008, 10:12:38 PM

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letsgetitracing

i am biding on a firewood job the guy had 1000 trees cut and logged out this past summer and i was wondering if anyone had a ball park idea how much wood in in 75 to 80 foot white oak trees the loggers took just the good logs and nothing more approx 25 feet or so and the tops are average of 12 inch logs and the average 6 of them per tree granted some are not this big but quite a few are bigger so i took average 

i came up with a ball park but open to suggestions
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woodmills1

Just for a starting point.  I have some pretty nice oak trees,  80 to 90 foot 14 to 26 inch dbh.  I would say that most of them would not give a full cord from the whole tree.  They are competition forest trees so most of the crowns are noy very well spread.  So I guess I am saying less than a cord per tree, unless yours have much more pronounced crowns.
James Mills,Lovely wife,collect old tools,vacuuming fool,36 bdft/hr,oak paper cutter,ebonic yooper rapper nauga seller, Blue Ox? its not fast, 2 cat family, LT70,edger, 375 bd ft/hr, we like Bob,free heat,no oil 12 years,big splitter, baked stuffed lobster, still cuttin the logs dere IAM

Mike LaMana

On this one I would work backwards: I.e. there may be original cruise data on the sale that had total BF/acre or cords/acre, and deduct from those totals the volume of sawtimber removed from the site.

Alternatively forget about the sawtimber harvest and develop a cruise dataset for an adjacent similar woodlot that gives the estimated total cords per acre. Deduct the approximate volume of sawlogs taken and there is your estimate of cordage. Volume of tops is a function of a whole lot of things, but especially stand stocking-per-are and so is very difficult to assess based upon a stem count only. Good Luck, Mike.
Michael LaMana, CF
LaMana Consulting Foresters
Mount Laurel NJ

Gary_C

Here is a firewood volume table from ISU Extension that may help.
http://www.forestry.iastate.edu/publications/F-338.pdf

Just roughly speaking, there should be about one cord per tree with half a cord in the top. However it depends on the DBH and height and you do not know that. If you know how many MBF were removed you could figure backwards at 500 bd ft/cord.
Never take life seriously. Nobody gets out alive anyway.

Ron Wenrich

We always used 1 cord/Mbf on the International scale.  The firewood guys said it held out, but, if you're getting a good overrun, why rock the boat.   ;)
Never under estimate the power of stupid people in large groups.

letsgetitracing

we did some figureing this summer and it's pretty accurate

diameter of log                               and cut at 16" length peices (standard firewood size)

4"                    it takes 110 pieces           it takes 133 feet to make a face cord

5"                    100                                             120

6"                    67                                                90

7"                    28                                                65

8"                    40                                                54

9"                    35                                                45

10"                  28                                                38

12"                  24                                                33

14"                  20                                                29


this figures are based on the  formula but based on 10" log getting 7 pieces and requiring 200 pieces for a face cord

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Gary_C

Those numbers are not accurate.  :)

For example on 12" logs if you stacked them one on top of another to make a four foot high stack, and then eight stacks side by side you would need 32 pieces to make a face cord, not 24 pieces. It will actually take slightly more than that when they are stacked normally and random sizes.

You are way off on the 4" also. It would take 288 pieces stacked in line to make a face cord. ::)
Never take life seriously. Nobody gets out alive anyway.

Ron Wenrich

Are you using square logs for your calculations?  Here's how I would work it out.  An average cord of straight wood will contain about 85 cubic ft of solid wood.  That number comes from the Forestry Handbook.  But that's for wood that is 4' long.  If we look at only the face, we'll get a surface area of about 21 square feet. 

What's the volume of a 12" round piece?  It comes out to 0.785 sq ft.  So, there are about 27 pieces of 12" round wood in a face cord. 

For the 4" piece, the volume comes out to 0.283 sq ft.  That would yield 75 pieces. 

Split wood volume would be a little different.  A face cord has 32 sq ft, but you can't fill it up with solid wood.  Even if you used perfectly cylindrical wood, you would have a solid wood volume of 25 sq ft for the face.  Then, your 32 pieces for 12" wood is real close, but for 4" wood, you would only need 88 pieces.

Of course, maybe I'm missing something.   ???
Never under estimate the power of stupid people in large groups.

Gary_C

Ron

I could not follow your calculations. You are quoting volumes in sq ft.

If you look at it the way I did, even if you stack the rounds in line with maximum air space in the "face" there is no way you can make a 4 x 8 face with less than 32 twelve inch rounds. The same for four inch rounds.
Never take life seriously. Nobody gets out alive anyway.

Ron Wenrich

Square footage is simply a volume calculation.  Your 4x8 face is 32 sq ft.  Since you are dealing with a face cord, the length of the piece is irrelevant.

But, you are putting a round peg into a square hole.  There's always air space, which is where the solid wood estimation comes in.  For perfectly cylindrical wood, you'll only get 25 sq ft of usable space in a 4x8 face.  That means you'll have 7 sq ft of air space and bark.  OK, I'm making the assumption that we're measuring inside bark.

But, wood is rarely perfectly cylindrical.  Some of its crooked.  So, I used 21.25 sq ft as the usable volume of the face. 

Since I have come up with the amount of usable volume available, I worked back to see how much volume there is in a round piece.  pi r^2 gives volume.  The radius of a 12" piece is 0.5 ft.  That gives me a volume of 0.785 sq ft.  Divide that into usable space, and you'll get the number of pieces.
Never under estimate the power of stupid people in large groups.

Gary_C

OK, I see the difference. When you are making the assumption of inside bark and drop down to 21.25 sq ft from the 25 it does reduce the volume. However if the wood is indeed pretty uniform and straight, you will have some unhappy customers when they find the stack less than 4 x 8.

The other calculation for 4" is not right. there should be 9 times as many 4" rounds as there are 12."
Never take life seriously. Nobody gets out alive anyway.

Ron Wenrich

You're right.  I forgot to figure the radius.  Instead, I used the diameter.  So, my 4" number reflects the number for 8" pieces.

For a 4" piece, the sq ft volume is 0.087 sq ft.  That comes up to about 11.5 pieces/sq ft. or 9 pieces in a 12" circle.

Never under estimate the power of stupid people in large groups.

letsgetitracing

i know that 52 cubic feet is a face cord of wood when run off a conveyor and i also do know that 3 inch pieces takes 225 to 230 pieces to make a face cord also i know that 4 inch pieces takes 200 to make same and 180 pieces of 5 inch

when we measure 3, 4, 5, inch piece we measure out side of pice to the point of the piece we stacked over 800 face cord the numbers are pretty accurate with in ten or so there is always a variable if they get split more squarish rather then a perfect pie shapped pieces.

we filled a truck with a box 17 foot long 42 inches high (3.5 feet) three feet on sides but four in the middle so 3.5 feet average. and the truck is 7 feet wide ran off the conveyor is exactly 8 face cord. of 4 inch pieces 1600 pieces no stacking involved in truck just at customers or we take it to the ware house and stack it on face cord rakc 4 foot by 8 foot all pieces are 16 inch long give or take an inch
Homemade firewood processor, 200 ton log spliter, 322 cat excavator, 966 c cat loader, 3 semis, 11 trailers, 50 ton low boy 12 inch tree chipper 3120xp 394 xp 372 xp 3 365  357 55 rancher 346xp 338xp  stihl 056 mag ms 290 026 echo cs440  4 cs3000's  jonsered 2165 2150

go BIG or go Home

Gary_C

There is a thread on the subject of measuring firewood in the crash archives. You can read about it here: https://forestryforum.com/board2/index.php?topic=289.0

Many states have defined the volumes required for a firewood cord. For a cut and split cord loosely thrown, it takes 175-180 cubic feet for a cord or 58.33 to 60 cubic feet for a face cord (1/3 cord of 16" long sticks).
Never take life seriously. Nobody gets out alive anyway.

SwampDonkey

Talking 100" wood here. And using my figures as a comparison from local experience.

A 16" balsam fir, 65 feet tall is around 1 m3 merchantable volume, taken down to 4" top. Equivalent to 0.4 cords. A 16" W. pine or spruce will have more volume because they are taller on the best sites compared to balsam.

A little more volume for hardwood on the best sites by NB standards (75-80 foot trees), close to 0.5 cord. Hard to factor in top volume because some major limbs can be pulp and there could be 3 major limbs or 6, whatever. So I believe my volumes are based on bole wood.

It all depends on how small you take the stove wood down to. Most will take it down to 2" here.


You have to have a pretty big tree to get a cord/tree. 12" hard maple trees usually takes close to 3 trees for a full cord and that's using the whole tree. The fire wood guys around here don't pay much attention to bucking sawlogs out of the harvested trees. The buts are slabbed for furnace wood, tops are kitchen stove wood. I think after you take the logs out your looking at 5 trees for top wood for your cord. But I guess that doesn't fit your situation, your talking 12" after taking the larger but log.

Are you saying the average but diameter of the remaining tops is 12". I don't get the 6 per tree bit, trees taper. How do you get 6 - 12" logs in the tops? Are those the average size of the but ends of the main limbs? Then from the 25 foot mark up to those limbs there must be a lot of waste. They must be bucked of at 20" or so. I'm in the dark, thus the speculation.  ::)

"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

wannabeonetoo

Just my opinion, but I think Mike LaMana has it right !  :P !(read below)
Steve

rebocardo

>  am biding on a firewood job the guy had 1000 trees cut

Bid according to a 1/4 of a cord for each tree over 16 dbh or every stump 20" to stay out on top.

So, assuming 1,000 nice trees and

$75 a cord for hardwood cut and split green ($150 seasoned)

1000 trees x ($75/4) = $18750 the money you can expect to make cleaning up someone else's mess ... which is what you are doing. How much you want to pay to take out $18,750 worth of wood cleaning up a mess is up to you.

You can expect any logger with 1/2 a brain has taken out any of the big wood suitable for firewood and splitting already if he paid the owner per tree and not by the load/scale ticket going out.

letsgetitracing

well then this guy had no brain because he paid him 1 hundred grand for the logs and never touched a top at all and never cut a tree down under 14 inch. there is average of 6 40 foot limbs starting on bottom of 14 to 15 in up to the leaves these are white oak he cut the logs and the tops sprout out

i'll get pics to show you there is  average of 3 face cord in every top

alot of the trees were 30 inch and some alot bigger i'll get pics of stumps also
Homemade firewood processor, 200 ton log spliter, 322 cat excavator, 966 c cat loader, 3 semis, 11 trailers, 50 ton low boy 12 inch tree chipper 3120xp 394 xp 372 xp 3 365  357 55 rancher 346xp 338xp  stihl 056 mag ms 290 026 echo cs440  4 cs3000's  jonsered 2165 2150

go BIG or go Home

SwampDonkey

Post edited for errors.

Makes sense now that I understand a bit more about the size. Man, what a wasteful logger.   Fly by the seat of the pants type, eh? :-X  As a I said a 16" hardwood would yield 0.4 cord, with all those massive tops combined it makes up for length, but not quite as much because the diameter is smaller. It's probably a fairly loose stacked 3 face cords. A full cord is a lot of wood chum. :)
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

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