How to calculate cord volume from log dimensions

[Red Horse]

Anyone have a method for figuring what you are going to get out of a log in terms of cord measurement. form example a stacked cord is 128 cu. ft. But that number includes the volume of the voids between the pieces. So let's say I have a log that measures 10' x 2' average diameter. that comes out to 31.4 cu ft. of wood or .245 cord. But once you stack that ,245 cord, it takes up a lot more space.

that my friends is the question- what is the best "fudge factor" to multiply the actual log volume to come up with a good "split cord volume. Just did a You Tube search and couldn't find any good info.

 

[murphy1244]

I would say between 5 and 7% of area.

 

[arrow]

Anyone have a method for figuring what you are going to get out of a log in terms of cord measurement. form example a stacked cord is 128 cu. ft. But that number includes the volume of the voids between the pieces. So let's say I have a log that measures 10' x 2' average diameter. that comes out to 31.4 cu ft. of wood or .245 cord. But once you stack that ,245 cord, it takes up a lot more space.

that my friends is the question- what is the best "fudge factor" to multiply the actual log volume to come up with a good "split cord volume. Just did a You Tube search and couldn't find any good info.

From my experience, a stacked cord of wood is supposed to measure 128 cu.ft. In actuality, there is closer to 80-90 cu ft of actual wood in a stacked cord.. You could use a log rule to measure cubic ft of a log and when you get to 80-90 cf's, it will stack closer to the 128.

If you do not have some type of log scale that measures volume in cu. ft., then you'd need to do some math. A calculator would help. Let's say the fallen stem is 18" in diameter and 30' long. We'll call this 1.5 ft in diameter . Divide this by two to acquire the radius and get 3/4's. Multiply the radius by the radius and then pi. (.75x.75x3.14) = 1.76 sq ft and then the log length x 30 and get about 52 cu ft. You'd need about two of this type of log to stack to a cord.

 

[Captain Dirty]

Anyone have a method for figuring what you are going to get out of a log in terms of cord measurement. form example a stacked cord is 128 cu. ft. But that number includes the volume of the voids between the pieces. So let's say I have a log that measures 10' x 2' average diameter. that comes out to 31.4 cu ft. of wood or .245 cord. But once you stack that ,245 cord, it takes up a lot more space.

that my friends is the question- what is the best "fudge factor" to multiply the actual log volume to come up with a good "split cord volume. Just did a You Tube search and couldn't find any good info.

When I was a lad my grandfather wanted stove wood (split, 12" long x <4" across) stacked in the woodshed so "a mouse couldn't get through it." Factor was very close to 1. He allowed that wood stacked outside to dry should be " loose enough that "a squirrel could run through the pile but the cat chasing the squirrel could not." I can only guess the factor. A woodcutter who was paid by the cord boasted he could stack cordwood (unspilt, 4' long x whatever) "so a dog could run through the pile." Factor was likely less than 0.5. Given crotches, knots, burls, etc. the factor will depend upon how small it is cut and split, how straight the grain is, and the skill of the stacker. Note my grandfather and the woodcutter had divergent interests.

Cut, split, and stack enough to join the woodsman's guild and your experience will tell you. Membership requires you not divulge your factor.

 

[Red Horse]

guys- thx for responses-right after I posted I did a search on MSN and came up with an Oklahoma State Univ. site that used 60 to 90 cu ft of wood as the equivalent of a cut/split cord. So If I split the difference, I come up with 75 cu ft of actual wood equaling cord of split wood.

so I will use a multiplier of 1.33 on my log volume. Ijust got "6 cord" of log length delivered. first log on the pile is avg "d" of 23" x 24' long.
My math says that is 69.2 cu ft. so 69.2 x 1.33 says I should have .92 cord out of that log.

I cut with a 20" bar and I like to split so max width dimension is 3 or 4".

 

[arrow]

guys- thx for responses-right after I posted I did a search on MSN and came up with an Oklahoma State Univ. site that used 60 to 90 cu ft of wood as the equivalent of a cut/split cord. So If I split the difference, I come up with 75 cu ft of actual wood equaling cord of split wood.

so I will use a multiplier of 1.33 on my log volume. Ijust got "6 cord" of log length delivered. first log on the pile is avg "d" of 23" x 24' long.
My math says that is 69.2 cu ft. so 69.2 x 1.33 says I should have .92 cord out of that log.

I cut with a 20" bar and I like to split so max width dimension is 3 or 4".

Your split dimension is good for drying time. I remember in 1973 a test was done to find what the best split size was for wood stove burn time and heat output and that was found to be a split of 6".

 

[KennyG]

The smaller you split wood, the greater volume it will take up when stacked. As a first approximation, calculate the volume of a square the log would fit into. In your example of a 2 foot diameter log, the actual volume of wood is a 2 foot diameter circle or 3.14 square feet. As an approximation, take a 2 foot square or 4 square feet, or 27% greater. That is probably a minimum increase in volume and if you have small splits it will increase more.

 

[Steppenwolfe]

Ya'll have me bringing up some old memories. When I was a younger man, I used to cut firewood for an old farmer. I trundled out to the woods, felled the trees, removed and stacked the brush, cut and hand split the wood, and would then stack into a pile about 4 x 5 x 8 to 9 ft. That way he was sure not to get cheated. I could do two cords on a good day, and he paid me 60 bucks. This was in 1980 or so. I also weighed 225 with a 33" waist. My wife is giggling now, wanting to know where that man went...

 

[Larry Caldwell]

In Oregon, https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/13600/EC1127.pdf page 18
In Missouri G5 How to Measure Trees and Logs | University of Missouri Extension Table 5
Tennessee just says 2.5 tons per cord.

 

[MAN IN BLACK]

A tree measuring 12" at breast height... should give you 1 face cord (4' x 16" x 8' )
And the statement is pretty accurate...I just don't remember where it comes from.