"Avoid wood with a moisture content of more than about 18%, treated lumber, drift wood, or any wood of a questionable source. Forget about species of wood. If it is dry, burn it.
Here's the BS about pine and softwoods compared to burning hardwoods:
Most softwoods have a higher equilibrium moisture content than hardwoods. In other words, if you kiln dried oak and pine then left them outside for 6 months, the pine, being partially hygroscopic, would absorb moisture from the air so its equilibrium mc would be higher than the oak. When burned, it robs valuable BTUs to dry the log so it can be pyrolized into combustible vapors and burned. This leaves less heat to maintain a strong draft and less heat to the room.
The popping you get from some softwoods is from burning green wood. The pops are actually steam explosions. When water converts to steam, it expands 1,600x at 212F. The higher the temps, the higher the expansion ratio.
The formation of creosote is a function of how hot the fire is burned, the flue gas velocity, flue dewpoint, and how complete the combustion. Modern EPA Phase II woodstoves burn the smoke twice. Open fireplaces burn it once but have very high levels of excess air thus diluting the air so the dewpoint remains low. Burning green woods tends to cool the stack temps, while adding moisture to the smoke and slowing the stack velocity thus increasing residence time allowing the tars in the smoke to condense on the flue walls forming what we call creosote.
A hot flue is a happy flue, I always teach in training.
Softwoods are good for starting fires while hardwoods last longer. While its true softwoods tend to be resinous and this sap (sugar) is combustible, the cell structure of the wood allows oxygen diffusion deeper into softwoods thus allowing faster pyrolyzation compared to dense hardwood cells. Need a good firestarter? Light a candy bar, potato chip or marshmallow.
Which has more BTUs? A kiln dried pound of oak or a kiln dried pound of pine?
HTH,
Hearthman"
"On a kiln dried basis, a pound of wood is a pound of wood is a pound of wood--they all have about 8600 BTUs per pound kiln dried.
The way hardwoods have more BTUs is density. A hardwood log of the same dimensions as a soft wood will contain many more BTUs because it is more compact or dense. Also, because the cell structure is tighter, it takes longer for oxygen to diffuse into the cells to begin pyrolysis therefore hardwoods are harder to get started compared to softwoods.
The Beagle makes a great point about size and shape. Hold a pencil into a flame to see how long it takes to ignite. Now, take another similar pencil, shave it into a "fuzz stic" and put it into the flame. It ignites almost instantly, right? You are getting the oxygen into more cells faster and the Heat Release Rate will support a flame front.
Be careful breaking up firestarters. If the mfr says don't then don't. I've investigated enough fires where this was done and the vaopr cloud of combustible gases from the wax billows out of the fireplace igniting combustibles on the mantel or nearby.
HTH,
Hearthman"
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