Who is more that 3 years ahead on wood and any complaints it's too old?

I think that is a good question. Do we have any chemists on the forum? A couple of things that make me wonder about it. 5 or so years ago a 200+ year old white oak blew over so I was able to get many loads of firewood from that tree. After seasoning, I was disappointed in the heat that I got from some of that wood...especially some of the larger limbs. The other thing is it seems that a 6" round burns hotter than a 6" round that was seasoned split in half. It might be my imagination but it seem that way so it makes me wonder if wood can lose energy as it seasons. Other than that, I would think that as long as it is dry, it is good!

So long as its not rotten then should be fine. Oak burns slower was it dry rot?

quotejso said:

So long as its not rotten then should be fine. Oak burns slower was it dry rot?

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I remember it had an odd dark color but it was not rotten. It was very dense with very tight growth rings. White oak normally pushes my STT to as high as I want to see it but this stuff just did not get it done.

Smoked said:

I think that is a good question. Do we have any chemists on the forum? A couple of things that make me wonder about it. 5 or so years ago a 200+ year old white oak blew over so I was able to get many loads of firewood from that tree. After seasoning, I was disappointed in the heat that I got from some of that wood...especially some of the larger limbs. The other thing is it seems that a 6" round burns hotter than a 6" round that was seasoned split in half. It might be my imagination but it seem that way so it makes me wonder if wood can lose energy as it seasons. Other than that, I would think that as long as it is dry, it is good!

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I'm not a chemist, but a chemical engineer in my former career.

Seasoning of wood involves several processes:

1) Evaporation of moisture (this is the important process for us wood burners)
2) Surface oxidation (you'll see the color change from freshly split to seasoned)
3) Evaporation of other volatile chemicals (which makes up wood's Volatile Organic Content or VOC). These VOCs are what gives freshly split wood its aromatic smell.

Dry wood burns hotter than wet wood (since the energy you'd otherwise waste on boiling off the water instead goes to heating your stove or other wood burner). You end up with a lower net energy produced per pound of wood burned (wet vs dry). Wikipedia suggests that "Moisture affects the burning process, with unburnt hydrocarbons going up the chimney. If a 50% wet log is burnt at high temperature, with good heat extraction from the exhaust gas leading to a 100 °C exhaust temperature, about 5% of the energy of the log is wasted through evaporating and heating the water vapour."

My "gut feel" is that oxidation of organics in wood related to surface oxidation produces only a dinky teensy tiny (that's a technical term, by the way) energy loss in the final fuel. If you ground a chunk of wood into fine sawdust and then allowed it to oxidize over time (constantly stirring the sawdust over time to expose new surface to the air, so that the entire surface of each little particle is oxidized), this energy loss might be more significant.

A 2005 PhD dissertation out of Sweden ( http://www.diva-portal.org/smash/get/diva2:24672/FULLTEXT01.pdf ) looks at the VOCs released from evergreen wood. Depending on the type of wood & how it's processed (split, ground into sawdust,...), the VOCs seem to run 0.5 - 5 grams per kilogram. At most, this is only 0.5% of the burnable organic content of the wood, so I don't think that this process would be responsible for any significant loss of energy when the wood is burned.

Over a LOOOOOONG term, bacterial/fungal degradation of your firewood may occur. Some of the organic content of the wood is gobbled up by wee li'l bugs. This will reduce the heat generated by burning the old wood to some extent. Once again, my "gut feel" tells me that this effect would be minimal, except on small diameter pieces of wood or larger pieces that have turned punky.

Excellent From here on we will refer all chemical related questions to Dr.JJ

As long as its not rotten, there is no such thing as too old. I had to replace a section of sill beam on my house a few years ago, and the salvagable chunks of the beam I cut out went into the stove.

That's 230 year old oak. Burned like coal

FYI, when they opened up Tuts tomb they found wooden chairs inside that could still hold a man's weight. That's 3000 year old wood.


Keep it dry and it preserves pretty much indefinitely.

Back puffs are more related to draft and stove design, I think. And maybe split size. Never an issue with my BK and 5-6 year seasoned oak that was low to mid teens on my moisture meter.

I'm about three years ahead and have two trees coming down in a couple of weeks to cut up. But with a new stove I don't know weather I'll be burning more or burning less. The new stove is more efficient, but will allow me to burn 24-7 if I wish. The other flip of the coin is that my first few years burning I had nothing but trash really. Mostly gum and cedar. Last year I started in on some oak and this coming season should be oak and hickory. I've done better about keeping everything dry and covered. I burn up the punks and chunks in the shoulder season.

Smoked said:

I think that is a good question. Do we have any chemists on the forum? A couple of things that make me wonder about it. 5 or so years ago a 200+ year old white oak blew over so I was able to get many loads of firewood from that tree. After seasoning, I was disappointed in the heat that I got from some of that wood...especially some of the larger limbs. The other thing is it seems that a 6" round burns hotter than a 6" round that was seasoned split in half. It might be my imagination but it seem that way so it makes me wonder if wood can lose energy as it seasons. Other than that, I would think that as long as it is dry, it is good!

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yes wood can lose energy over time. The wood contains volatile chemicals which will slowly gas off into the atmosphere. These chemicals provide a significant percentage of the energy in wood. Really old wood will have a much lower BTU value, basically just the carbon in the cellulose combusting to CO2. I believe about half the energy content in wood is volatiles which could potentially be lost in older wood.

Wish I had more time to google this, but a quick search turned up nothing definitive. But I do know that the volitales in wood are a pretty small %, see this link. They would be part of the "extractives". http://www.paperonweb.com/wood.htm
I have some 6 year old black locust I got from a neighbor that is very gray in color on the outside, inside still looks like newer samples that I have. I'd love to throw some of each in a bomb calorimeter and see if there is substantial difference. I'm sure the study has been done, hopefully someone will find it.

planner steve said:

Wish I had more time to google this, but a quick search turned up nothing definitive. But I do know that the volitales in wood are a pretty small %, see this link. They would be part of the "extractives". http://www.paperonweb.com/wood.htm
I have some 6 year old black locust I got from a neighbor that is very gray in color on the outside, inside still looks like newer samples that I have. I'd love to throw some of each in a bomb calorimeter and see if there is substantial difference. I'm sure the study has been done, hopefully someone will find it.

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Yes, but about 60% of the heating value in wood is contained in the gasses produced by the pyrolysis of the wood (this is what is consumed in the secondary combustion and catalytic converters of wood stoves). I wonder if any of this energy is lost in old wood? Over the weekend, I burned some wood in a fire barrel during a party. This wood was from a tree that had been cut down a very long time ago (I would guess at least 20 years ago). The wood burned very hot and very, very fast. I have never seen wood consumed so fast.

I've burned wood that was stored in a barn for 20 years and the only problem I had with it was not having more of it.

jharkin said:

FYI, when they opened up Tuts tomb they found wooden chairs inside that could still hold a man's weight. That's 3000 year old wood.

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Yea, but the real question is how well did those chairs burn?

Not counting rotted wood? Then no, I have no complaints.

I am at least 4 maybe 5 years ahead, never had any problem. Not always the best drying weather around here. I have had Hickory and Oak take up to 4 years to dry out. Course part of that is stack placement but ya do what you can. My Ideal location would be the front yard. That ain't going to happen-city would get all bent out of shape. As it is I am way over their idea of reasonable amount.