How much firewood is in a tree?

1 cord in a 22 D tree.

A lot. Sorry I cant help, But holy cow thats a wide tree! Do you have the equipment to handle it? I have had oak rounds 18-20" across x 16" long that took 2 people to lift in the truck!

Kind of an interesting question... you're apparently talking about a deciduous tree, since a Douglas fir with a base diameter of 6-7 feet would be about three times that tall, with by far most of the wood mass in the main stem; pretty easy to calculate roughly. On the other hand, big oaks (for example) have proportionally more wood mass in the branches after they've split from the main trunk. A lot harder to estimate, I'd think.

And I mean "estimate" from the perspective of someone who has no prior experience of actually cutting down such a tree and measuring the resulting stacked firewood, in order to get a real-world sense of the proportions involved.

--But having said that, I have no idea what I'm talking about and am open to scornful corrections.

Make some assumptions and you can get a rough number. You know the base diameter. Take a guess at what the diameter would be at the top where you stop using it for wood.

Average the two. Calculate the volume of a cylinder with that (average) diameter. That would be the volume of unsplit wood without any branches.

Multiply by a percentage for the increase in volume due to splitting (10%?).

Then take a guess at how much the branches add.

This should at least give you a rough idea.

Refer to this. Its for determining how much standing cord in a given area, but it breaks out rough ideas based on trunk diameter

http://ucanr.edu/sites/placernevadasmallfarms/files/76320.pdf

Take the average diameter of trunk say its 2 feet with that size butt end. Multiply the the length of the trunk 60 feet x the radius squared (or half the diameter 1 times itself) equals 1 multiply that by pi or 3.14 equals 188 cubic feet. Then multiply by 1.25 for airspace in typical stacks equals 235 cubic feet split and stacked. Divide by 128 cubic feet in a cord equals 1.84 cords. Now comes the fun part the limbs. It varies by species but an old oak might add another 30% while an elm might add 10%. In a typical case your looking at 2-2.5 cords if I did my math right.

drewberry24 said:

Thanks for the replies. I went and checked it out today, and it is a big hickory. We are guessing about a cord and a half with the nice big limbs. Not sure where he came up with 7 feet wide though, but it's still a good sized tree. We'll be taking it down in the next week or so.

Click to expand...

let us know what it works out to in cord volume.

I cut down a big leaf maple a couple/three years ago. It was ~80' tall and an easy 3' at the butt. Got 1.5 cords out of that all said and done.

Maybe he was talking the circumference of the tree instead of the diameter.

Hah! Do I see Willey in that picture? If you are dropping it I could see some good footage coming from a Go Pro attached to the saw! Can't put my finger on it but that looks like a local campground.

A cord is 128 cubic feet of split, stacked firewood, but only about 85 cubic feet of solid wood. Figure the volume of the trunk and divide by 85.

If the tree is 6 ft diameter at the bottom and 4 at the top, then average diameter is 5 ft diameter. The area of a 5 ft diameter circle is Pi r^2 = 3.14 x 2.5^2 = 19.6 square feet. multiplied by the length of 60 ft you get 1177 cubic feet. Divide by 85 cubic feet per cord, and you get 13.9 cords of wood.

That is a lot of cords from one tree, but a 6 to 7 foot diameter, 60 ft long log is a huge log. Did you mean to say that the tree is 60 ft tall, meaning the trunk is a lot less than 60 ft long. Even if the trunk is 20 ft long and 6 ft wide, you'd get something like 1/3 of the volume I calculated, or around 4 cords.

You can adjust the calculations according to how large the trunk is. You could calculate the volume of large branches if you know the dimensions of each one.

Wood Duck said:

A cord is 128 cubic feet of split, stacked firewood, but only about 85 cubic feet of solid wood. Figure the volume of the trunk and divide by 85.

If the tree is 6 ft diameter at the bottom and 4 at the top, then average diameter is 5 ft diameter. The area of a 5 ft diameter circle is Pi r^2 = 3.14 x 2.5^2 = 19.6 square feet. multiplied by the length of 60 ft you get 1177 cubic feet. Divide by 85 cubic feet per cord, and you get 13.9 cords of wood.

That is a lot of cords from one tree, but a 6 to 7 foot diameter, 60 ft long log is a huge log. Did you mean to say that the tree is 60 ft tall, meaning the trunk is a lot less than 60 ft long. Even if the trunk is 20 ft long and 6 ft wide, you'd get something like 1/3 of the volume I calculated, or around 4 cords.

You can adjust the calculations according to how large the trunk is. You could calculate the volume of large branches if you know the dimensions of each one.

Click to expand...

85/128=.6666. Are you telling us that a properly stacked cord is 1/3 air? I've looked at many a row of wood and I never see clear through 1/3 of the time when looking at one. Sure, not every piece will be perfectly square and straight but there is absolutely no way that your fact can be correct for evenly cut and well stacked wood. (It is more like 105-110 cu feet on the freshly stacked cord)

Another way for you to look at it is that the area of a circle drawn in a square is .785 that of the square. So the ratio of volume of a cylinder in a rectangular box would be the same. At 85 cu feet (or .666) to the cord you are telling us that once cut and split a cylinder of wood will stack into a box that is 1.19 times bigger than what it would have fit in to start?

If you ask the woodheat.org guys where their 85 cu foot factoid came from they will tell you that it wasn't from a properly measured cord, it was from samples of what people were calling cords. They wanted to find out how much wood was in what people were self reporting as cords. They were not out to find what an evenly cut, well stacked and measured cord of wood contained before it seasoned and shrank.

Nah, your overthinking it, drop it, buck it up and split it. If you wind up with too much (if there is such a thing) then sell the extra, or at least that is what I do.

What size saw/bar you going to tackle that hickory with?

I think the 85 cubic feet of solid wood per cord comes from the US forest service. I can't recall exactly where I read it.

So is that Hickory on the ground yet? I might have some free time this weekend if you need it dropped. Hopefully there is a big empty area next to it.

Ahh, glad to hear. I am just about to start up my personal wood processing for the year. Gotta transfer all the seasoned wood to the racks near the house so I can get this load of red oak split and stacked for 2016 wood supply. I came across this and couldn't turn it down, I need to get some more maple or gum for next year.

One thing about wood heat.. it warms you several times.