Need help calculating cords from logs

[njtuna]

i am going to get some red oak from town, downed from a windstorm on march 1st. they are looking to get rid of it, the more the better. the trees range from 24in in diameter to larger. they are willing to cut into 6ft lengths to make it easier to handle for me, and drop it off in my driveway. i really couldn't ask for more. i would like to figure out how many 6ft lengths i can take from them. i can definitely take 2 cords, maybe three- have to speak to the mrs. is the formula for a volume of a cylinder: V= pie*r-squared*height the way to do it? 128sf per cord? i know there has been some dicussion about this. thanks in advance

 

[acer saccharum]

Make them 4' long, and 2' in diameter. Stacking them two high and 4 wide would give you exactly one cord. So 6' long makes 8 logs equal to 1.5 cords. Obviously when you cut/split and restack the volume taken up by air and wood will change. As I recall others have said that when you cut and split the rounds it grows.

 

[Haywire Haywood]

Check out the stickies.. There are links to log weight, cords per log... etc etc..

Ian

 

[goatchin]

i've punched a couple numbers using board foot measurements...203 bf/face cord-14" long. this number probably is not very close b/c i've only measured/calculated once.

BTW the formula i used is: (0.79D squared -2D-4) L/16

 

[Husky137]

An accepted rule of thumb that I have used with accurate success is 500 BF of logs equals 1 cord. This is using the International 1/4" log scale.

A log that is 6' long and 24" on the small end has 160 BF.

http://www.timberbuyer.net/sawlogbf.htm

 

[rmihalek]

is the formula for a volume of a cylinder: V= pie*r-squared*height the way to do it? 128sf per cord? i know there has been some dicussion about this. thanks in advance

The formula is technically correct, but the variable for firewood is how much air is mixed into your cord. In other words, there are many ways to stack a cord of wood in order to end up with the legal definition of a 4 foot by 4 foot by 8 foot stack. There is tight stacking (nice, square split pieces stacked all parallel) and there is loose stacking (bent, crooked pieces all stacked criss-cross).

It seems reasonable to assume a tightly stacked cord of wood will be about 20% air. So, you can take the formula for the volume of a cylinder, multiply by 1.2 and get a good estimate of what a split, stacked volume of firewood would measure out to be.