Firewood Optimum moisture content can wood be too dry?

[Oaktree]

The drier the wood the more BTU’s it will produce. Heat is required to boil off wood moisture and allow the wood to vaporize. Dry punky wood will weigh less and produce less heat. Wood should stabilize at the current air moisture content.

I don't think I've ever had any such thing as firewood that was "too dry". As someone else noted, I try to rotate my woodpiles so I'm burning 2 year old wood each year...it's as dry as it's going to get, and any longer if exposed to any weather at all will start to get punky.

There are the same amount of BTUs in soft maple as in white birch... I don't generally waste my time with either. I have mostly rock maple, beech, and some ash for hardwoods on my property; because anything else with any size went to the local paper mill years ago when I bought the property. Having said that in early fall before the rains start I usually go out back and pick up whatever is dead and lying around, if all that I want is to take the chill off. Hemlock is a quick heat, then burns out fast so that you don't need to start opening windows.

I've never had much luck with hemlock...the few times I've tried to burn it I had a helluva time getting it to ignite. It would just sit there and smolder. Fortunately, I've never been so hard up for firewood that I've had to use it. I'll use some softwood (spruce, pine) in my shop, but not in the house.

I have no problem with white birch, it's good early/late season wood when you mostly just want to take the chill off in the evening, but don't really care if it burns all night. Don't think I've ever had red maple, not very common here.

White pine is the worst firewood out there, for sure.

Nah. At least it's good for kindling or if you want to heat up a workshop (for example) quickly. Poplar or Aspen has got to be the worst. Really high moisture content green, but even when it's dry it doesn't burn very well, again just tends to smolder and not put out any heat.
Unfortunately, my property has an abundance of it.

 

[goeduck]

Another nice thing about some species that makes them good firewood is how easily the rounds split and the shape of the splits. This is Douglas Fir. The bigger ones from a forest have so few knots other than at the top of the tree where the canopy is, so they split very well.

 

[goeduck]

Poplar or Aspen has got to be the worst. Really high moisture content green, but even when it's dry it doesn't burn very well, again just tends to smolder and not put out any heat.
Unfortunately, my property has an abundance of it.

I do burn some poplar. As you say it has a tremendous moisture content when green, I read 51%. Horrible to split. But ours does dry out and starts burning in the stove easily. It turns to coals very well, then I use that to light the better wood. We all have to burn what we have access to, right? So it would not be my choice, but I adapt to it. The rest of it goes to the burn pile.

 

[Egon]

Wood with high moisture content splits quite easily at minus twenty degrees F.

Dry poplar burns well. Really good for kindling. Dry punky poplar, which many get in moist ares does not burn well.

There are places where firewood will be limited to poplar or conifers with some areas relying on chips in the past.

There are tables which pretty well tell you the density and btu’s with corresponding moisture content of woods.

 

[CobyRupert]

The drier the wood the more BTUç—´ it will produce. Heat is required to boil off wood moisture and allow the wood to vaporize. Dry punky wood will weigh less and produce less heat. Wood should stabilize at the current air moisture content.

Many stoves have warnings about using processed lumber.

True. I believe you aren't saying dry wood contain more BTU, just that the BTU's of wet wood are spent (wasted) boiling water into steam that goes up the chimney, thus you get more usable BTU's from drier wood.
So can wood be too dry?
Similarly I think most stove setups have a natural (let's call it) "radiation rate" or btu burn rate that is most efficient; where the heat transfers to the stove, the stove to the air, new cool air comes by the stove to absorb the heat etc...versus the heat going up the chimney. That is, the heat in that stick is transferred to the room at an optimum rate over time. The flip side is if smoke is cooled too much (by having to boil moisture, or a long stove pipe, or a cold exposed chimney, then wood gas condensation (creosote) can form.
IMHO, there's a balance in burn rate for optimum efficiency and heat transfer versus creosote, versus etc..

I don't have any real data or studies to confirm, but I suspect that "too dry" wood can burn so fast that much of the heat can be lost up the chimney, depending on it's type/weight, etc.. It can also burn so fast that it becomes hard to control/damper the air to it. All the wood gases are coming out at once and unless you have a way to transfer it to heat and transfer the heat to your room the wood may be too dry.
:2cents:

 

[Deere Dude]

I am getting half a dozen oak trees that tipper over in a wind a couple months ago. What is the best way to handle that. Leave in logs then chunk and split and store as needed or cut rounds and let them lay in a pile outside for a year, then split and store? For me, dryer ones seem to split easier.

Would it change much if rounds were stored on a concrete pad vs. on the lawn?

 

[4570Man]

They cut and split best green and they dry the best in firewood form.

 

[52farmer]

I am getting half a dozen oak trees that tipper over in a wind a couple months ago. What is the best way to handle that. Leave in logs then chunk and split and store as needed or cut rounds and let them lay in a pile outside for a year, then split and store? For me, dryer ones seem to split easier.

Would it change much if rounds were stored on a concrete pad vs. on the lawn?

I would cut ,split and stack in the sun and wind off the ground as soon as possible, if your planning on burning next winter.My opinion only,dont have any data, just past experience .

 

[/pine]

If there's room to store them I stack logs (mostly red, white and chestnut oak) until it's easy to knock the bark off...let them dry for a few days after removing the bark and then process them into firewood...

Storing split wood with the bark on for any length of time gets really messy once it comes loose while drying...Also most insect larva is under the bark and has time to mature and infest the wood...not that burning some worms and borers hurts anything but their dust etc. adds to the mess at the wood shed and once carried inside...

 

[Oaktree]

I do burn some poplar. As you say it has a tremendous moisture content when green, I read 51%. Horrible to split. But ours does dry out and starts burning in the stove easily. It turns to coals very well, then I use that to light the better wood. We all have to burn what we have access to, right? So it would not be my choice, but I adapt to it. The rest of it goes to the burn pile.

I don't even try to burn it. Any that come down get cut up & dumped in the woods to rot.
As you said, you've gotta use what's available where you live, I just get grapple loads every 2-3 years of hardwood (mostly maple and ash, some birch).

They cut and split best green and they dry the best in firewood form.

+1 on that. When cut & split you want to stack it so it's off the ground. I use a row of pallets (there's a field full of them somewhere if you need any ).
Bring a year's worth into the shed in the fall.

Storing split wood with the bark on for any length of time gets really messy once it comes loose while drying...Also most insect larva is under the bark and has time to mature and infest the wood...not that burning some worms and borers hurts anything but their dust etc. adds to the mess at the wood shed and once carried inside...

That seems to depend on where you live and the type of wood. Not a big problem here.