how many mbf in a cord of wood?? (oak)

[a old timberjack]

 i been looking all over, i read it somewhere how many board feet in a cord of wood 128 cubis feet 4x4x8 i guess it is a stupid everyday question you always forget., thanks....... Brandon

[Gary_C]

The conversion depends on both the diameter of the logs and the bd ft scale you use. But despite that most people use the standard factor of 500 bd ft per cord or 2 cords per MBF.

[ljmathias]

Still trying to get my mind around this- so 4X4X8 is the same as 2X4X16.  So if I had 16' logs, 12" in diameter, I could lay down two logs wide (2') and stack them four logs high, right?  That means 8 12" logs 16' long- how would this scale out then, same as indicated at 500 bdf?

Lj

[Phorester]

Nope.

If you were dealing with nothing but cubic feet of solid wood, say two boxes of wood chips or sawdust, then both 4x4x8 and 2x4x16 will give the same volume.

But that won't hold up when dealing with real logs.  Remember that logs aren't perfect cylinders, there is taper from one end to the other.  Most volume tables are based on the diameter inside the bark (dib) of the small end of a log.  So the question needing an answer is, where on the log would your 12" diameter be measured? 

That means the analogy of 4x4x8 versus 2x4x16 won't hold for bd ft or cord comparisons, even though it's the same cubic foot volume.

[Tom]

It's also important to realize that you are using two different measuring scales.  Board footage, is used for determining the lumber or timber, by volume, in sawlogs.  The board footage scale uses inside the bark measurements and is written to favor certain sizes of logs. 

Generally  a cord is considered 4'x4'x8' of split and tightly stacked firewood.  Sometimes a cord is a weight measurement in the neighborhood of 5500 pounds, depending on species, size nad weather.

Accept for some local communication, Face cords aren't a legitimate measure and are not used legally to report sales.

The quantity 500 board feet per cord is just a general rule of thumb that approximates the board footage in a scaled or weighed cord.  Variables that would effect it are log size, branches, knots, holes, rot, sweep, as well as the type of  mill used to break it down.

[Climber]

Theoretically / mathematically ONLY
1 cord = 4x4x8 = 128 cubic feel
board foot is 1"x12"x12" or 1/12 of cubic foot
12 BF is 1 cubic foot
12 BF in each cubic foot x 128 cubic feet in cord = 1,536 BF in cord.

It is theoretically / mathematically ONLY and NOT practically
Climber

[Rocky_Ranger]

It's also an apple and an orange, your board foot is solid and the 4X4X8 is not.  Solid cords run 75 - 85 cubic feet of wood.  Depends on the log size, and the fact most "cubes" figure on Smalian's formulas.  Nat Cruise figures cubes and boards, they run the gamut from 425 bd ft/ cord to 675 bd ft/cord.  Maybe even more, those arre just the ones I see - mainly around 550 bdft/cord.

[Jeff]

Theoretically / mathematically ONLY
1 cord = 4x4x8 = 128 cubic feel
board foot is 1"x12"x12" or 1/12 of cubic foot
12 BF is 1 cubic foot
12 BF in each cubic foot x 128 cubic feet in cord = 1,536 BF in cord.

It is theoretically / mathematically ONLY and NOT practically
Climber

Absolutely not practical, or possible.

[ljmathias]

Hey, thanks for all the great replies: I think I'm getting it but stop me if I'm wrong- trees are round, boards are flat... or am I getting close yet?

Lj

[Blue Sky]

A cord of wood in these parts is a stack of wood 4x4x8.  Green 4' logs.  When you cut that stack of logs up into cut and split pieces, it reduces to a stack approx. 100 cu.ft.  Is this true, anyone out there.    Enchanted Forester

[RSteiner]

I have always wondered why or how the unit of measure for cordwood would be used for measuring lumber.   ???  Both are volume measurements but in a very different form. 

Lumber measurement is the volume of one solid piece where cordwood measurement is the voulme of space many pieces take up.  An old Machinery's Handbook I have lists the volume of a cord of wood as 128 cubic feet, a pile 4'X4'X8'.  They figure a pile of cordwood to contain a solid volume of about 70 cubic feet, so 58 cubic feet of the cordwood pile is air.
I think the soild wood number for cordwood is more for determining weight than BF volume.

At those figures there would be 800 BF to a cord of wood.  That could be high depending on the diameter and defects in a log.  The 500 BF figure sounds more like it.

Randy

[maineframer]

Around here white cedar is sold by the cord, not by the thousand. That rule of thumb is helpful.

[woodmills1]

the max I can get on my trailer is 1500 bd ft of logs and it holds 3 cord of firewood......do the math. :D

[SwampDonkey]

The loggers and wood cutters here are old school. They only understand cords, something they can scale off with a 4 foot pulp stick. Tonnes, board feet, m³ and they want it converted.

[Gary_C]

Let's change the question slightly. If you are looking at a standing tree, how do you determine the cords or MBF in that tree?

Say you are marking a stand for cutting. You look at an 18 inch DBH Hard Maple and you know all the trees in this stand are 60 feet tall. In one case say the tree will not make a sawlog and it is pulp. How many cords?  In the other case, it is a log tree. How many MBF?

[SwampDonkey]

We mark based on basal area, crown closure, and quality. And stands are rarely marked here, wouldn't be 1% of harvested volume. We tried to push it for years, but it didn't take. Only thing that's marked is perimeter and trails on 99.99% of sites. In mature hardwood and softwood 24 m²/ha equals 24 cords/acre as a rule and used as a quick figure before doing the math at the office. And believe it or not it's very reliable. ;D  Mature cedar, hemlock and white pine throw that out the window because of taper. White pine for instance grows 15 meters taller than spruce and fir.  We measure and compile based on metric m³, and convert to cords using figures for 8' wood, or 4 if there is a 4 foot pulp market. Log volume is a crappola shoot for hardwoods and no one up here scales hardwood logs on standing trees. As a general rule for 'potential' hardwood sawlog trees we equate 60-70% of the volume to pulp and 30 % of the softwood sawlog volume is pulp. Anything smaller than spec is just pulp. Because quality is so poor in hardwood, it is bid on for pulp and sometimes a deal is struck to pay 50% of log price for good logs and veneer.

[Gary_C]

I guess I have some idea how you scale a tree for MBF from DBH, but are there tables that give you cords based on DBH also?

[Ron Scott]

Yes, there are board foot tables and cordwood tables to determine a trees volume in board feet or cords. There are also cubic foot tables.

When marking and cruising the timber we determine if the tree is sawlog or pulpwood by species, size, and quality and then record the tree's diameter and merchantable height. This data is then entered into a computer program which determines the trees volume by board feet to an 8 inch top (International 1/4 scale) and cordwood to a 4 inch top, plus any additional cordwood in the topwood.

The computer then calculates the total MBF and cordwood volumes by species for sale. 

[RSteiner]

This is all very interesting.

Randy

[Phorester]

From Gary_C:    "......but are there tables that give you cords based on DBH also?"

Yep.  Want me to mail you one?

[Gary_C]

From Gary_C:    "......but are there tables that give you cords based on DBH also?"

Yep.  Want me to mail you one?

Sure, I'll PM you my address. Thanks for the offer.

[SwampDonkey]

Gary be aware of site index with any of these tables and suppression usually drops you down a class because height is restricted like where you have aspen beating the tops of the fir. Here in my area I have 4 index curves each for softwood and hardwood. One table don't fit all sites, unless you get what we call the average. ;) My table 5 and 10 are the averaged sites. 1-4 are softwood, 6-9 are hardwood.

[SwampDonkey]

I guess why we use total merchantable volumes in this region is we have total utilization. Ok, say you have a pile of chips off the planer mill over here, then a pile of sawdust off the saw and over there the jacket wood and another pile of hog fuel (bark and rot). And finally the lumber stacked for drying. How much volume (estimated basis) of each of those piles came from my land, Joe's land and Dave's land? My woods harvest was covering 50 acres, Joe's 80 acres and Dave's 15 acres. By using total merchantable volume, measured at dbh outside of the bark you know how much of each off each guy's land by scaling for the whole log, not just recoverable lumber. Seems to me unless that jacket wood and bark is tossed away someone has themselves a stacked deck. And they are selling pulping and hog fuel material that isn't being accounted for in the cruising and scaling to pay the owner of that timber. I know from the stand point of a lumber based mill you are only interested in saw material yield. But, the rest of that material has value where I come from, even though there was an additional cost to produce and move it. See why we can't use board footage scale around here in most instances? ;) We do use board footage scale on hardwood logs and veneer, and some softwood log markets. Most softwood logs are scaled on m³, cords and tonnage. But anyone can understand that price is adjusted in those scales for what isn't used as lumber. You know very well it is. In these days, it's a matter of make or break a mill when average piece size decreases like it has in the north. ;)

[Okrafarmer]

and convert to cords using figures for 8' wood, or 4 if there is a 4 foot pulp market.

SD, is there still a 4' market?  ??? I haven't spent a winter in Maine for a while. When I was a kid we could watch the trains go by with thousands of cords of 4' pulp logs on them, and all the old oncelers were out beating the bush with their jitterbugs and pulp hooks to take 4' fir and other species to the paper mill. Do they still take 4' any more? I thought modern efficiency had finally done away with that.

[Buck]

Hey, thanks for all the great replies: I think I'm getting it but stop me if I'm wrong- trees are round, boards are flat... or am I getting close yet?

Lj

Pie are round and cornbread are square.  Hah! food for thought. :D

[SwampDonkey]

Yip, there are.

KATAHDIN PAPER COMPANY - East Millinocket, Maine

VERSO PAPERS - BUCKSPORT, Maine

FRASER PAPER - Edmundston, NB

Not long ago we had a hardwood veneer market for 4' maple and birch. ;D

As a further for instance: You guys have firewood guys working for beer money, well same thing always went on at some mills, 4' pulp for beer money. Yup pickup loads at a time. :D

[Okrafarmer]

Yip, there are.

KATAHDIN PAPER COMPANY - East Millinocket, Maine

VERSO PAPERS - BUCKSPORT, Maine

FRASER PAPER - Edmundston, NB

Not long ago we had a hardwood veneer market for 4' maple and birch. ;D

As a further for instance: You guys have firewood guys working for beer money, well same thing always went on at some mills, 4' pulp for beer money. Yup pickup loads at a time. :D

Whoa. I'm amazed the mills still put up with it in this day and age, where a tractor trailer of logs can be loaded and unloaded so much more efficiently. Around here I've never seen 4' logs for any reason unless it was firewood and even then that's random lengths that happen to sometimes be near 4'. Firewood is also a much more casual commodity in the south than it is in the north. Even people who heat exclusively with firewood rarely need more than 2 cords a winter down here, unless they burn pine-- which some of them do.

[Gary_C]

Donk, it's just the end of September and you are digging up threads that are two and a half years old and reopening them????

It's going to be a long winter by this measure.  : :

:D :D :D

[g_man]

A cord of wood in these parts is a stack of wood 4x4x8.  Green 4' logs.  When you cut that stack of logs up into cut and split pieces, it reduces to a stack approx. 100 cu.ft.  Is this true, anyone out there.    Enchanted Forester

That is they way it works where I live in VT

[SwampDonkey]

We call 100 ft³ of solid wood a cunit. But that firewood isn't solid obviously. The cunit was used when purchasing by the cord, and converting to wood substance. It was a quick way to convert from a slick scale on the truck. One saw mill still buys on cunits near here the last I heard. The price was better than Irving, but never as good as Fraser's. My intuition tells me it wasn't 100 ft³ after all. It's like Ron says, no matter what scale you sell on the price is adjusted. :D

Gary, I'm not ready to hang my saw up yet for the year. ;D

[chucker]

550 mbf for a band saw... circle saw 500 mbf is the going figure for a cord of 8" small end 100" sticks to a cord that is 4x4x8 = 128 cf! a cord of blocked wood cut to 16" lengths will produce a total of 120 cf!  a cord of blocked/split an stacked  will produce a total of  measuring out at 4'x16"x22.5 feet in length..... according to the grass routes  wood cutter pamplet handed out at out local fuel assistance office. as can be seen from their figures there is about a 8 cf. loss from sawing each 16" block from an 8' length/cord equaling a 120cf cord of sawed wood... thrown randomly into a conveyance for delivery it would total a sum of 160 cf.... which is a standard for sales here in centeral minnesota....

[Okrafarmer]

convance = conveyance?

[chucker]

 :D  "THANKS"  excuse the dumb fingers hey? lol

[4x4American]

Theoretically / mathematically ONLY
1 cord = 4x4x8 = 128 cubic feel
board foot is 1"x12"x12" or 1/12 of cubic foot
12 BF is 1 cubic foot
12 BF in each cubic foot x 128 cubic feet in cord = 1,536 BF in cord.

It is theoretically / mathematically ONLY and NOT practically
Climber

I typed into google, how many bdft in a cord of wood, and it told me 1,536, which I knew was way off.  Now I see how they figured!

[BEEMERS]

Ive recently had an experience with this..cord versus mbf.I believe when selling by the cord you are selling the volume of wood within that 4x4x8 ft area including bark,slabwood and air space between the logs.
By the board foot or thousand board feet the buyer is buying only the lumber he can calculate that he can get from each log and any air space or waste he is not buying..
I sold some 14 foot oak recently..I knew what I had in cordage..he scaled inside the bark on the small ends..and there was a good bit of taper as these were 14'6 and mostly butt logs.
Anyway..I lost 2/5ths scaling as opposed to cordage..He was paying 500 per thousand..I guess that should be in at $250 per cord..I got $155 a cord but that's fine..I get that he didn't want to pay for what he wasn't going to get in lumber.
This was black oak,nothing special.

[David-L]

How about the guy who set up a cord of 4' wood split and dead end stacked to make 4x4x8. Then he took 2" x4" woven wire garden fence and placed it up against the wood up right and then proceeded to count air space within the 2"x4" wire squares and came up with only 84 cubic ' of solid wood in the 128cu/ft pile. I beleive it was in the woodland Steward a few years back. Think he had time on his hands and most likely was a wood fanatic. Not really a bad thing to be though.

[SwampDonkey]

Air space on the ends of sticks does not translate to the whole length of the sticks I'm afraid. ;)

[lynde37avery]

One cord of firewood pulls behind my skidder just the same as 500bf saw logs.

[Plankton]

Still trying to get my mind around this- so 4X4X8 is the same as 2X4X16.  So if I had 16' logs, 12" in diameter, I could lay down two logs wide (2') and stack them four logs high, right?  That means 8 12" logs 16' long- how would this scale out then, same as indicated at 500 bdf?

Lj

This thread is almost as old as I am but I ran these numbers real quick. Kinda interesring.

On international  scale which is used around here, a 16 ft 12" top log is 95 bdft. So 8 logs are 760 ft.

But obviously there logs so at the but end the logs stacked would be "larger" then a chord anyways. The calculation only works if they have no taper.

If I pulled 8 16s at 12" and bucked them in half and piled them it would stack up to be over a chord.

I think 500 ft per chord is accurate enough, I average around 500 ft behind the skidder ussually and I have been pulling pulp last few days and a chord pulls exactly the same as around 500 ft. Logger math!

[cuznguido]

 :D :D Eight years, one month and a few days and we still don't know.  Tis indeed cold outside.

[David-L]

SwampDonkey, I was wondering the same thing. We forget though, he probably had an engineering degree and had an equation to average out air over the 4'.

[SwampDonkey]

I have seen, and I know it is done, where you have large piles of wood strung along roadside in tree length form. They will use an average length and depth of the pile every so often and use tree length tables to estimate volumes. They usually do several samples. These piles are long and high, it's not feasible to scale every stick. It's all going to be weight scaled at the mill anyway for the final tally. It's more or less done to track the wood and production. Machines now can scale every stick as it's processed.

[Peter Drouin]

Machines now can scale every stick as it's processed.

Is that in the woods or at the mill?

[SwampDonkey]

Woods

[barbender]

     If the operator has his machine calibrated correctly, our Ponsse processors will usually have volumes tallied right on the money.  They keep it logged on the machine computer.

[drobertson]

Not an exact number for certain, had a friend try to figure this years ago, before I knew of the FF,  wanted to know if the value 0f logs would be worth more if converted to firewood,, back when the flooring market kinda dropped and log prices went down, as did a lot of things, anyway the number given early on in this topic of 500bd/ft is pretty darn close,  I converted 8 logs that scaled 520bd/ft, into firewood just this year, and the stack all though not measured, memory serves me that this is a very reasonable estimation.  We have all busted some big ones that fill a stack pretty quick, and others where one split gives only two chunks,  I did a dozed tree just after building, big ole red oak,(before the mill was here) that tree produced 6 face cords, so that's a lil better than 2 cords,  so a thousand bd/ft may have been in that tree,  uh,, interesting, I never figured it till now :D  fun stuff to mull over, now back out to the wood pile, oh boy,, (feeling lazy today) nerve pain gots me down a little this morning,

[drobertson]

went out and split just one log, 8'8" 55 bdft on the INT, scale  busted and stacked as tight as possible,


  

 
a real good measurement, 4' by 3' by 16"  I called it one foot,, figuring for air gaps,  12 cuft. if I figured right it would take 550+ bdft of logs to produce a cord of firewood, close as I can get or ever will again,, nice to know a closer ball park number,, these are pretty close,,

[4x4American]

Ain't scientific experiments fun? lol

[svart ole]

500 bf in a cord is a fair guess in most cases. It all depends on the quality of the wood and size. At some point it gets back to the old saying about making a silk purse out of a sow's ear. If you are a sawmill man you know about swindle sticks a.k.a. log rules. In general there are 3 in common ones in use. This link will address all three and call out some of the differances between them. http://www.forestry-suppliers.com/t01_pages/pdfs/1211_ScaleStick.pdf

If you are trying to make money sawing the logs you buy scaling can get as complex as you want to make it. This is very true if you as a buyer are trying to be fair to the person selling you wood and make sure you are getting what you are paying for.

If you have the time to read this and understand all of it you will be well on your way. If nothing else it will be a eye opener.
http://www.fs.fed.us/im/directives/fsh/2409.11/2409.11-NF%20LOGSCALING%20HDBK.pdf

[RSteiner]

I realize this is an old thread but I was looking something up in the Machinery's Handbook, mine is the eighteenth edition printed in 1970, and they had a section on wood weights and volume.  A cord of wood is a stack 4' wide, 8' long, and 4' high.  That figures out to 128 cubic feet.  Now we all know there are a lot of air spaces between those pieces of wood and the Handbook estimates there is 70 cubic feet of solid wood per cord.  That being said a cord of wood should contain 843 board feet.  Here's how I reached that conclusion, a board foot is 1" x 12" x 12" which equals .083 cubic feet ( 12 x 12 = 144 divided by 1728 ( the number of cubic inches in a cubic foot ) which equals .083, so 70 cubic feet divided by .083 comes close to 843 which would be the number of board feet in 70 cubic feet or a cord of wood be it pine or maple.

My figuring could be suspect as I graduated in the half of the class that made the top half possible.

[Gary_C]

Hey, thanks for all the great replies: I think I'm getting it but stop me if I'm wrong- trees are round, boards are flat... or am I getting close yet?

Lj

Pie are round and cornbread are square.  Hah! food for thought. :D

These two quotes point out the flaw in your thinking. Boards are not composites of all the solid material in a cord. The part that goes missing is variable and depends on the diameter of the rounds turned into squares.

[NWP]

When scaling a log, the board feet figure only takes into account the wood that will make lumber and not the waste. When cutting and splitting a cord of wood, all of the log is used(bark,slabs). I've produced a cord of wood from 12" logs Doyle scaled at a little over 300. The bigger the diameter, the more board feet it takes to make a cord because there isn't as much waste.