OK, I’ve been laying in firewood for the winter and for the first time I’ve started wondering how much wood I use in a winter.

Measuring firewood is something that I’ve always found to be troublesome. It has been my experience that firewood is measured entirely by volume, and the actual wood content within a given volume is highly dependent on the way the wood is cut, split and stacked. I guess it is too much trouble to measure it by weight, so we’re pretty much stuck with measuring by volume.

The standard volume measurement of firewood is a “cord.” A “cord” is “defined” (and I have the scare quotes because it seems to be a rather loose definition) as a stack of wood 4 feet high, four feet deep and eight feet long. Which is a total volume of 128 cubic feet.

Of course nobody buys wood this way. Firewood is actually cut to fit into more or less standard sized fireplaces and wood stoves. The most common length of a split log seems to be 16 inches. That’s certainly what fits in my stove, which is almost exactly 18 inches from back to the glass window on the front door. Sixteen inch lengths are more or less perfectly sized for our stove.

Sixteen inches is 1 ft, four inches. Multiply that by 3 and you get 4 feet. So one “cord” should give you three stacks that are 4x4x8 feet. But this is where the stacking gets tricky. trying to stack splintered wooden logs so that they butt up against each other is pretty much impossible, so what they do is they lay out what is called a “facing cord” which is a stack of wood 4′ x 8′ x 16″, or 1/3 of a cord. Frequently people purchase “facing cords” not actual cords. Some people don’t even realize that a facing cord is not an actual cord.

As it happens 1/2 cord of firewood pretty much fills up a standard pickup truck bed, so one common technique to measure out firewood is to simply fill up two pickup truck beds and call it a cord.

But if you don’t have a pickup truck (as I don’t) your measurement technique is usually to measure it before you stuff it in the back of your SUV.

Of course for me this year I haven’t purchased any firewood, instead we had a bunch of trees last year that I had to either cut down because they were too close to the house, or else because they were dead and were fire hazards. I cut down about eight trees last year and burned the wood for most of last winter, but I still had a good bit left this year. I also took my deck down last year and now have a lot of wood that is really not fit for using to build anything so I am cutting it and stacking it like firewood.

My stack of split wood logs is roughly 5′ x 15′ x 16″, and my stack of “cut lumber” is roughly 5′ x 10′ x 16″. Multiplied and added that’s roughly 167 cubic feet of wood, or about 1.3 cords. However, I believe the cut and stacked lumber is much denser than the split logs. I still have a large pile of lumber left to cut and stack, but it’s a pain in the tail to do so, so I’m wondering how much I actually need to have cut and stacked to get through the winter.

Each log probably averages about six inches high by six inches thick by 16 inches long. Figuring about an inch of wasted space in each direction, I’ll say that from the cord stack they average about 7″x7″x16″. That means my neatly stacked pile of cut logs holds roughly 220 split logs, or would hold that many if all of them were the same size. Of course some are larger and some are smaller, but they probably average out to about this. My stacked lumber should account for another 150 logs or so (even though they obviously aren’t “logs”). Still, that means I have the equivalent of about 370 logs worth of split wood. Which would keep the upper floor of the house warm roughly 37 nights.

Of course since winter starts at this altitude in October and doesn’t end until April, it’s pretty clear that there are more than 37 nights to deal with.

BUT, we are talking about “seriously cold” nights. “Normally cold” nights usually only use up about four logs. And there aren’t that many “seriously cold” nights. Last year I’d say we had about two dozen, and that was a bad winter. But using it as a guide, that would mean that the wood I have already laid out should handle all of my “seriously cold” nights plus about 30 “normally cold” ones. That’s where the unfortunate aspect of this comes in. Becuase I’m sure we had about 90 “normally cold” ones. Meaning I’m roughly 60 “normally cold” nights worth of wood short for a full winter’s wood burning. That means I need the equivalent of another 240 or so logs to get through the winter. If my math is right that means I need about another 15’x5’x16″ stacks of wood. I probably have that much left in the deck wood still stacked out in my yard. Based on the cutting and stacking I’ve already done, that’s about ten hours of work to lay in that much wood.

I guess I better get to work.

Isn’t math fun?