I was reading somewhere that if you have a log an are trying to estimate how much firewood is in it, that 90cuft is a cord. I can kind of believe this, because when you stack it, there is air space in 128cuft were a log is solid Has anyone else heard this?
I thought this paper contained some very interesting info on how Firewood compares to other fuel sources for BTU's. It also talks about how much wood is in a split cord and estimates the average to be about 80 CF. Also discusses that your freshly stack cord of 128 Sq. FT. may shrink in size by 8%. It's an interesting read... http://www.forestandwoodland.org/uploads/1/2/8/8/12885556/wood_fuel_for_heating.pdf
Of course there is air space in stacks. Of course a cord measures out to 128 cu ft. but I don't think anyone anywhere sells cords as solid. Some math fan somewhere must have had time on their hands and tried to educate all of us wood burning trogs. I think there was a thread (or at least a topic) already that ruffled a few feathers!
I believe wood shrinks. So much that my wood piles fall over after a few seasons. Lol I am good at cutting and splitting, but suck at stacking.
Yes that is around the number we are taught in school to use. But in forestry school not much time is spent on firewood. But we still talked cords although it's more old school unit of measure you still have to understand it and the old guys refer to it more. But the legal definition of a cord is 4x4x8ft which equals 128cuft. That is a cord is a cord, period. But because trees are round and you can't stack wood into solid cubes there is air, just as in firewood. So you use anywhere between 90 to 110 cuft of "solid wood per cord". But you never refer to this number, it is still sold by a loosely stacked cord and referred to it that way. Sent from my SM-G900V using Tapatalk
And yes wood shrinks, that's why green or dry cords are referred to in firewood. Sent from my SM-G900V using Tapatalk
This!!! It’s best at about a year or so to compensate for the shrinkage of wood to satisfy the stablized measurements of a cord. I know this might vary and add to Dave’s can o worms comment but hey it’s only an educated response as the kinda wood that grows here is good at a year, great at 2 and best at 3 years.
I guess my point is the 90cuft number is irrelevent unless say your converting to BTUs or some science based paper. Air has no BTUs. So how much actual wood is irrelevent to talk about. Because you will never have square trees unless you cut them into cants or something prior, so there will be air space. Thats a given. If someone sells green firewood they and you should expect 128cuft of wood delivered. If you buy dry there will be more wood than if it was green, this is just another small reason it should cost more than green wood but most of that is because its been aged.
tight stacked cord 128cf less 10% for air space numbers I use- 3 year dry- about another 10% volume wise for shrinkage
For estimating I just consider a round log to be square. Air space gets built in automatically. Math is much easier. It comes out to 100 cu feet of solids or 21% air space. Close enough. As for the shrinkage after drying, I would put forth the argument that your cord measured prior to shrinkage isn't a cord any longer.
That would be displacement volume and no one measures firewood in displacement volume. AS much as estimating the volume of a conical tube may be an interesting mathematical means for estimating the potential cordwood yield one does have to consider the make-up a typical stack of cordwood in the final cordwood estimation.
