Some thoughts on ignition speed

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Tom123

Burning Hunk
Oct 11, 2014
176
East Granby CT
I seem to think that species and moisture content being equal, the side(s) of a split without bark will ignite faster than wood with bark. I also think that the exposed inner wood from a split will ignite quicker than the debarked side of a split or round. Any thoughts?


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I always used to try and keep as much bark on as i felt losing it was wasting good btu's. After doing to experimenting with it i found bark to hold moisture, even from humidity, for quite some time. I debark any chance i get. Splits light faster and burn cleaner.
 
I switched to all spruce two seasons ago. Spruce bark makes nasty flakes in the carpet with sharp edges on them, takes forever to dry and is hard to ignite compared to spruce wood.

I do have plenty of birch up here, I suspect birch bark would be the exception that proves the rule that bark is hard to ignite.
 
If the bark is starting to come loose and to come off I help it whenever I'm restacking. It's where all the bugs and moisture reside so for me it dries better and is cleaner w/o it. Maple bark is not as bad as some, hickory too and the little bit of ash I've had seems even better but oak makes a mess and cherry's even worse. Both rot easy and turn to wet buggy mulch. Usually not much use for fire starting by the time I'm ready to burn it.

Whenever I top cover from the get go it helps but most of my stacks seem to spend at least a year out w/o cover and the bark holds the rain the bugs move in. The little bit of my wood where I manage to keep the bark clean and dry throughout drying does catch well but I don't get that much.
 
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I believe keeping it dry and covered is key.
 
I always used to try and keep as much bark on as i felt losing it was wasting good btu's. After doing to experimenting with it i found bark to hold moisture, even from humidity, for quite some time. I debark any chance i get. Splits light faster and burn cleaner.
II have loads of wood this year where large amounts of bark are popping off as I split. Like you I hate to waste BTU's (at least I think the bark is additive BTU's) so I just toss it in a big pile. I then bring it inside via wheel barrow and let it dry out for a few days. I have been adding a bit to each fire this fall, throw in a bunch towards the end, etc. Seems to work, just appears to create a lot of extra ash.
 
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90% of my wood is dead standing Red Oak with no bark left on them. The best for getting the fire going have a 1/4” to 1/2” of dry punk on the out side. Any live oaks that may get blown down I give away so I don’t have to deal with the bark or the long seasoning time.
 
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I'll go against "against the grain",

IMHO, wood dries the quickest when the maximum amount of surface area is exposed to the air with plenty of sun and wind. Because of that I split the wood into what I call "board split". Meaning that the splits are in rectangular pieces that are uniform in thickness rather than pie shaped wedges.

These end pieces aren't the greatest example because they are intentionally about twice as thick to crib up the ends of the stacks.

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You can see it better on the black walnut, great campfire wood BTW, smells good and burns with a blue flame.

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I'll go against "against the grain",

IMHO, wood dries the quickest when the maximum amount of surface area is exposed to the air with plenty of sun and wind. Because of that I split the wood into what I call "board split". Meaning that the splits are in rectangular pieces that are uniform in thickness rather than pie shaped wedges.
I think you are correct, and I think I have the math to prove it. :) There was a discussion a while back about drying times (see here) and what I found in a study was that the drying time is proportional to the thickness of the split raised to the power 1.52, which means that thicker pieces of wood take exponentially longer to dry. In other words, a split that's uniformly 2" thick will dry (overall) more quickly than a pie-shaped split that ranges from 0" to 4" thick.

Back to @Tom123 's original question, the wood that ignites most easily should be the part with the greatest surface area-to-volume ratio. That's IF (big if) the MC is uniform. The reason is that combustion needs heat and oxygen; a small piece of exposed wood will heat faster and be surrounded by air while a flat face will heat more slowly (because the interior of the split is a heat sink) and have air on only one side. So rougher is better, and thin pieces are better than thick.
 
Wood split that small would never work for me! It would burn up and be gone like the wind! I stay far enough ahead that it gets seasoned out..like 4-6 years out..I prefer 6x6...8x8 pieces to fill the stove with....she will cruise all night putting out serious heat....just the way I like it on those bitter cold nights.
 
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Some good reply’s here, I was hoping this discussion wood go this way. Thanks everyone.


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I believe keeping it dry and covered is key.


I'll disagree, IMHO exposure to sun and wind and time are what effects wood seasoning. I find even in the winter time split wood is losing moisture. Rain on top of dry wood is superficial and only effects it for a day after the rain is done. MC readings are taken on the inside of a fresh split anyway and rain does not effect that at all.
 
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I'll disagree, IMHO exposure to sun and wind and time are what effects wood seasoning. I find even in the winter time split wood is losing moisture. Rain on top of dry wood is superficial and only effects it for a day after the rain is done. MC readings are taken on the inside of a fresh split anyway and rain does not effect that at all.

IMO & experience, yes exposure and time are important. But top covering also helps, and keeping moisture out of the middle will make it go faster. Rain & snow melt will go straight down into a wood pile if not top covered, quite easily. It would take longer for the weather to dry that stuff out of the middle of the pile afterwards. We get lots of thaw/freeze cycles here during the winter, and without top cover the middle of the pile will be a block of ice into the spring. Especially toward the bottom. I double stack which makes that situation worse but top covering also helps with single stacks.
 
IMO & experience, yes exposure and time are important. But top covering also helps, and keeping moisture out of the middle will make it go faster. Rain & snow melt will go straight down into a wood pile if not top covered, quite easily. It would take longer for the weather to dry that stuff out of the middle of the pile afterwards. We get lots of thaw/freeze cycles here during the winter, and without top cover the middle of the pile will be a block of ice into the spring. Especially toward the bottom. I double stack which makes that situation worse but top covering also helps with single stacks.

If this forum has taught me anything it is that there are always a lot of different answers to go along with all of the variables when it come to wood heat.
We get our share of winter weather (its snowing like crazy right now) but I have never seen the 'block of ice' thing happen in my wood piles. I am sure that the different climates and locations have a lot to do with what works best.
In my experience, I stack and split in a double row. My wood pile locations are open, windy and sunny so that helps a lot. I leave the piles uncovered most of the time, I only worry about covering them for a month or two before I bring them in. I cover them to keep the surface moisture off when the fall rains come. As long as I get two years to cure, they are very dry. Bark or no bark it doesn't matter. It the bark comes loose, I toss it aside or save it for kindling. Another tip that I always use is to stack with the bark side up. That way the bark will shed the rain instead of catching it.
 
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Yes it's the freeze & thaw & freeze that does it, and we get a lot of that here.

For example - yesterday it was -5c and we had 3-4 inches of snow on the ground. It was +8c and pouring rain when I woke up today. Right now it's back down close to zero and tomorrow morning it's supposed to be -9c. When it does that with a foot or two or few of snow on in the middle of winter, multiple times, it makes ice like crazy. And drives the snowmobilers nuts, lol....
 
I'll disagree, IMHO exposure to sun and wind and time are what effects wood seasoning. I find even in the winter time split wood is losing moisture. Rain on top of dry wood is superficial and only effects it for a day after the rain is done. MC readings are taken on the inside of a fresh split anyway and rain does not effect that at all.
Fresh green split wood sets here uncovered the first summer/winter and then it gets rotated in and stacked along my drive 3 face cord/cord deep. I stack this way as it is my only option for maximizing my storage.At this point it is covered and stays covered until the final rotation into the winter staging area for what I am burning that winter...it works very well for me as I stay well ahead of the game.Hopefully all goes well with the solar kiln I am planning for this spring and then this will all be a mute point...:) Then it will be shake and bake!
 
This was taken in October, this part of the pile was split about January. It will hit 20% by November. Note the thickness of the splits, these dry quicker being relatively thin and have a lot of surface area.

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I seem to think that species and moisture content being equal, the side(s) of a split without bark will ignite faster than wood with bark. I also think that the exposed inner wood from a split will ignite quicker than the debarked side of a split or round. Any thoughts?
I agree with your observations.


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Note the thickness of the splits, these dry quicker being relatively thin and have a lot of surface area.
I too "board split" at least 50% of my stuff. It deff speeds the drying process. However, for me I top cover day 1. Wood is very susceptible to humidity and my drying area, while not wet, stays a little moist unless it's been several days without rain (located downhill, slightly shaded). Rain soaked into the stacks raises the local humidity and prevents optimal drying......for me. If I could stage my stuff out in the open, exposed to full wind and sun were rain water dries within hours, I prob would only cover it the year it's getting burned. For now my rubber roofed stacks are keeping me on schedule and the house warm with ease.
 
I leave all my new fresh split wood uncovered for a year. Then cover it. I have found that with the bark on, even oak 4 years seasoned has quite a bit of moisture under the bark, but it is only surface wetness. The moisture level is still very low.