MPBN WEB EXCLUSIVE
Focus on Firewood
Barbara Cariddi: And Pete, what have you got going here?
 Pete Lammert: I have a demonstration going of how a fire burns when you're dealing with green wood and the amount of energy that you're going to waste trying to burn green wood--not even considering the problem of this smoke that's full of compounds that will cause creosote in your  chimney. But if you could just look at the demonstration here, we're talking about a cord of soft maple, which is going to find its way into every wood pile this winter. A cord of green, soft maple has 168 gallons of water in it, just to get it down to 20% moisture content. And if you go ahead and burn green wood right now, the heat from underneath the wood is boiling off the water in the wood, and that's represented by the steam coming out of the ends of those sticks.
BC: You can actually see the little bubbles of water coming out there.
PL: Yes. And sometimes people ask me why does my wood hiss? Why do I have hissy wood? And that's because your wood isn't seasoned or even dry enough.
BC: So how long would someone have to leave firewood, let's say out in the yard, before it's considered dry?
PL: The definition of "seasoned" that I use is cut, split and open to the sun for the three summer months. And June was going along pretty well into July. We had some wonderful drying weather, and then we've gotten into this rainy spell and I dare say, wood that has been left out in the yard, dumped in the grass, is probably as green now as the day it was dumped there.
BC: So it's very inefficient to burn green firewood. But it's also dangerous, isn't it?
PL: Yes. It is because of the creosote problem.
BC: And what is the creosote problem? Explain what that is.
PL: Ok. The creosote problem is, the smoke coming out of green wood has about 203 different component compounds, and when that smoke goes up a chimney, and the chimney is cool, it's called the dew point--the weathermen and their famous dew point--the temperature inside that flue is cool and the smoke condenses on the wall and, if I may I'll grab a piece of smoke pipe with creosote in it and show you.
BC: Ok, great.  
PL: Ok. The dry material on the surface is one of the three forms of creosote. It's a dry or flaky one. The majority of the compounds in it have burned out. The nasty one is this black, shiny one, which is basically a tar, and that's called milk pitch creosote. And when your chimney takes fire, that's what burns, and you can get temperatures in excess of 2000 degrees on that. If you don't have a good solid chimney and a well-lined chimney, that's going to raise havoc. And that's why you should call the fire department if you're having a chimney fire.
BC: So how often should you clean your chimney? I mean, creosote is going to build up even if you have dry firewood eventually, isn't it?
PL: Yes, just because of the nature of the chimney, it's never as warm as I want it to be. I sweep my own twice a year. I do it just before Christmas, when the hard burning starts, and then in April or May after the heavy use has been over. And for the six to eight cords that I use, I get about two five gallon pails of this dry creosote out of my cleanout.
BC: And there must be a way to stack firewood so that it dries out as effectively as possible.
PL: There is. A little lesson on wood--a stick of wood has cells in it and they're like little short straws. And when you stack firewood, you want the prevailing wind to be blowing by the ends of the pile.
BC: So you've got some wood stacked over here. Let's go look at that.
So we've got three tiers on the pallet. What does that mean?
PL: Because most people buy 16" wood and because most pallets are 48" wide, people will stack it three tiers, and think that they've done an absolutely wonderful job. Well, in this particular case, being up on those utility poles, that's a good part of the stacking. They got it up off the ground. Number two, there's no grass growing around it. You'll see a picture in a moment of grass engulfing a pile of wood. The problem here is that this is just one mass of sticks of wood, and the air can't flow past the ends of the inner pieces. And if we could just adjourn to the other end of this pile, I'll show you a version that will dry this pile at least three times faster than this one here.
 BC: So in other words, don't stack each stack right up against the other stack.
PL: Right. Don't butt the tiers together. Otherwise, you eliminate the possibility of air flowing down through it. There is a recipe for drying wood and it's a wonderful recipe. It's the three T's: time, temperature and turbulence, and the time is dependent upon the temperature above 40 degrees and the turbulence is wind flow. So if you have 100 degree temperature, and 100 mile an hour wind, your time is like three days.
BC: I see.
PL: Here's an example of the middle tier missing and the pieces of wood that you see between thepilesare just stickers that hold the pile up to keep it from tipping over. And then, if you go to any lumber yard in Maine, over in the rubbish pile, there are these lumber wrappers and if youask, they'll probably give you as many as you like, and to me, this is a free tarp. And if you notice, we don't come down over the edge.
BC: I noticed that.
PL: We just go on the top, because, I'll show you down here, if you come down over the edge, it makes a moisture barrier up top and the moisture that evaporates up and hits the bottom side of the tarp can't get out. Now, here we're getting to almost the perfect pile. They put it on pallets, they put space between the pallets, they put a roof on it, the ubiquitous blue tarp, that didn't come down over the edge. But, if they could have just put some space between here--in other words, if they could have gotten another three or four pallets and made four separate piles like this last picture down here, this allows the air go down through and maximizes the drying on either end.
BC: So if you don't have pallets, is it ok to stack them on let's say 2 X 4's, or even some logs or something?
PL: Stack it on anything that will keep the moisture away. If you look down there, the bottom board on  the pallet got wet, but just four inches up that upper board on the deck is dry. And it's even better overhere, with the pallet on the utility poles because they give us an eight inch--no that's more 10 inch--lift. So that's even better. That means the air can get underneath the pallet, which means the pieces that are lower to the ground will have a chance to dry.
We haven't talked about softwood. Softwood is one of the pieces of information that isn't dealt with but this year, people are probably going to be getting softwood. There is a problem with softwood because of the pitch in it. This is an eastern white pine slab and you can see right here that all these little dots are dry pine pitch, and that has a terrifically high energy value, or fuel value. The problem is it burns so hot and so fast, you've got to be careful when you're burning softwood that you only burn a little bit at a time. If you fill your wood stove with dry pine slabs, as much as you would fill it with hardwood, and just get it going and put the damper down and walk away, you could come back to a house that's full of smoke and the red trucks and a lot of excitement, and possibly even a fire, a meltdown, because of the high heat value in this material.
BC: What are the best woods to burn?
PL: The best woods to burn are the densest, the heaviest woods to burn, and we don't have much shag bark hickory in Maine but that gets up near the top of the list. Otherwise, we have black locust and honey locust, the two locusts, beech, yellow birch, sugar maple, then red maple. And here's ash right here. Ash is 15 percent drier than any other species out there, so if you want to get a little bit of a leg up, if you're burning green wood and they agree to bring you a load of ash, that's another little hint that will save you some drying time.
BC: What about oak?
PL: Both red oak and white oak--white oak is a very dense wood, it's right up there in BTU (British thermal units, a measure of energy content] value because of its density, but again it's harder to dry. And red oak: It seems that the old timers--the standing joke was, yeah, red oak is fine for two years.
BC: And then what?
PL: Then you can burn it, but it takes twice as long to season it.
BC: So how do people know whether they have a whole cord of firewood?
PL: Today, the majority of wood delivered to homes comes in trucks that have wire cages on them, and they're loaded at the firewood processor and the state has a standard--180cubic feet of space has to be occupied by a cord of wood that 12 or 16 inches long or 195 cubic feet of space if the wood is 2 feet long.
BC: Let's say it's 16 inches long, which is your average, how would a homeowner know whether they have a cord?
PL: Well, after the truck has dumped it, they could climb into the truck body and measure it,but mostofthese guys have their truck bodies built to that 180 cubic foot measurement because that's what thecurrent state law is. When you stack it, you might have more or less, just because of the way the wood falls off the conveyor into the truck body.
BC: All right, Pete Lammert, than you so much. You've been a huge help.
PL: You're welcome.
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