How many cords in a tree

[Eric Miller]

Is there a simple method to estimate how many cords of split wood are in a downed tree or log?

Also, which would contain more wood, a cord of split wood or a cord of rounds?

 

[sweetheat]

the eye ball test. No the only way to know for sure is to split it and stack it into 4X4X8 foot piles. then you're still only close. i'd think the split is packed tighter, so more wood. Maybe their's a formula. sweetheat

 

[woodmaster]

search for log volume calculators . you will need to input small end diameter and length of logs.

a cord is roughly 500 board ft.

 

[ISeeDeadBTUs]

Split wood of which you speak is what, Apprentice??

 

[Eric Miller]

OK, woodmaster gave me the idea to look for a log volume calculator but they calculate Doyle, Scribner or International units, which measure the amount of lumber that can be extracted from a log. I wasn't able to make use of these directly but it got me thinking.

A cord (4x4x8) contains 128 cubic feet. Of course, wood doesn't stack perfectly so there is not 128 cubic feet of solid wood in a cord. After some Googling, it seems reasonable to assume about 85 cubic feet of solid wood per cord.

Next, the volume of a cylinder is Pi x radius squared x length. A tree tapers as it grows so it is not a perfect cylinder; I am assuming a taper of .1 inch per linear foot. To calculate the volume of the log I calculate the volume twice -- once using the diameter at the large end, and once using the diameter at the small end and then take the average of the two. I got that idea here: http://mathforum.org/library/drmath/view/61034.html

I made a spreadsheet where I can plug in the dimensions of a log and it will estimate the value in cords. I will test it the next time I cut and stack firewood.

In any case, to get one cord of stacked wood, I calculate it would take a single log 31 feet long, with a diameter of 24 inches on one end and 20.9 inches on the other, which equals 85.5 cubic feet. And there doesn't seem to much difference between split or rounds becasue if you took that 31 foot log and cut it into four foot sections it would pretty much stack into a 4x4x8 foot area. Does that sound reasonable?

 

[kenny chaos]

10" diameter at breast height - usable height of 32' = .133 cords

20" - 32' = .59

There is a great chart somewhere on line but I only saw it once several years ago.
No, it's not a simple equation, works on a curve.

As for the above example, my chart shows 24" diameter at breast height, 32' long would equal .88cords.

 

[SE Iowa]

I never was good at math.

10” diameter at breast height - usable height of 32’ = .133 cords

20” - 32’ = .59

How exactly does 20 inches minus 32 feet equal .59 cords?
How does 10 inches minus 32 feet equal 0.133 cords?

 

[kenny chaos]

Those were two examples I took off my chart. It reads; A tree with a 10" DBH (diameter at breast height) and a 32'log will yield .133cords. I used those two examples because it appears that one tree is twice as big as the other but it yields more like four and half times the firewood or -Not an easy equation!
Here's a chart I just found- (broken link removed to http://www.familyforests.org/research/documents/Estimatingstandingfirewood.pdf)

 

[grego]

As far as whether there is more wood in a cord of split or a cord of rounds; a hillbilly neighbor of mine in the Ozarks claimed there was more wood in a cord of rounds because "nobody can stack it as good as God". I always kind of liked that.