Can fire wood be too dry?

[MAX-24-Dean]

US Forest Service used to have a publication (document) that showed moisture content of cord wood for every state and some other nations. According to the document there is a point where the wood reaches an equilibrium for the region you live in and does not dry out as fast once it gets to that point.
Lowest moisture content was around 13% for wood that had been cut to cordwood lengths.
To get it any dryer than that it would need to be kiln dried.

 

[BnRidge]

In our climate the lowest moisture content cordwood stored outside will reach is about 13-15%. I have a 15yr old EPA tube stove (Jotul Oslo), and 15% wood works very well with it. We did cut some apple wood about 50yrs ago, and had it stored in the shed, and a recent gauge reading indicated it was about 7-10%. I thought that old apple wood would be better, since it was drier. Oh nooo. I think the stove is designed for wood around 15%, and if it were designed for dryer, things may have worked out. The dry wood off gassed so fiercely that it was difficult to control. Very small loads worked well. But then the whole design intent of long burns and even heat was thrown off. I moved the apple wood aside and went back to outside air cured cordwood. Stability and contentment has been achieved.

 

[Egon]

Pound for pound wood has equal btu content.
Moisture in the wood has to be vaporized which requires heat.

 

[CobyRupert]

Pound for pound wood has equal btu content.
Moisture in the wood has to be vaporized which requires heat.

The only effect I’ve found with “too dry” wood is when you don’t have to “spend” btu’s vaporizing water into steam that goes up chimney, is the wood burns hotter, gasifies faster, which requires more oxygen to combust. It can be hard to control the fuel/air/heat balance that produces a steady output.

Either oxygen starved unburnt gas is going up the chimney, or the fire is roaring and exhaust/chimney temps are getting too hot, or the stove can start “pulsing / blowback” as it gets into a cycle of air igniting the hot gas (almost explosively), but then snuffing/ or choking itself out because it consumed all the air and can’t get enough. It then repeats the cycle of reigniting when more air drifts back in. (Very much like a paper fire in a wood stove).
All this happening about 4 times a second with my stove. She’s a thumper!

 

[MAX-24-Dean]

US Forest Service document on moisture content Equilibrium by state and close city.

 

[plowhog]

oak has more ash than madrone.

My typical firewood is some oak, some madrone. I have had the same experience. Rarely shovel ash even after many fires using madrone. Not so with oak ...

 

[ultrarunner]

Or stacked in Death Valley...

Split Seasoned Coastal oak makes for a wonderful fire... use to have lots of friends on the call list when one toppled... but those days gone with all the burn restrictions.

Curious how much ash when burning ash?

US Forest Service used to have a publication (document) that showed moisture content of cord wood for every state and some other nations. According to the document there is a point where the wood reaches an equilibrium for the region you live in and does not dry out as fast once it gets to that point.
Lowest moisture content was around 13% for wood that had been cut to cordwood lengths.
To get it any dryer than that it would need to be kiln dried.

 

[BnRidge]

My typical firewood is some oak, some madrone. I have had the same experience. Rarely shovel ash even after many fires using madrone. Not so with oak ...

The ash content of bark is 5% to 10%, and cordwood alone is .3-.6%
Oak can have quite a bit of bark.

 

[Jstpssng]

On a slightly different note, I found the first time that I did a beanhole what wood not to use. Somehow wood from an ash tree doesn't produce many coals.

 

[lilranch2001]

I was once told by a forester that bark is the only thing on a tree that has any real nutritional value for plant life. The actual wood has little to no value.