# Firewood Comparison Chart



## WOODplay (Jan 26, 2011)

Take a look at this site...

http://chimneysweeponline.com/howood.htm


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## Adabiviak (Jan 26, 2011)

Neat... didn't expect dogwood to be that high up there. No California live oak? It's my fave.


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## soupy1957 (Jan 26, 2011)

Unfortunately, since I don't cut down my own trees, or cut up fallen trees, I'm at the mercy of the guy or gal I choose to buy from.  Typically, a wood load will have a mix to it.  Some very desirable woods will be in it, and then again, perhaps not so much so.  I'd be hard pressed to be able to call around and see if I could buy exclusively one preferred type of wood (say "Black Birch" for example, that has a very high BTU rating).

Would I LIKE to get the most BTU's out of my wood that I'm burning?  Sure............

-Soupy1957


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## dannynelson77 (Jan 26, 2011)

This chart was just recently updated and all figures where downgraded a little.  Would like to know the explaination as to why but I dont see it?  For instance They used to have Red Oak and White Ash at about 24 MBTU.  Now they are at about 22 MBTU.  Also, they now have Honey Locust higher than Black Locust.  It used to be vice versa.  And its almost like they just rounded numbers with so many woods being exactly the same MBTUs now.  They used to be more specific or exact with each type.  Just makes me question the vailidity of the comparison.  I know its just a guide but not sure why all the changes......


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## billb3 (Jan 26, 2011)

climate change ?
Younger forest ?

I've several old dogwoods  around the house.
I've had to trim some small and some larger branches.
It's hard as a rock to cut. I expected it  to be up there on BTU.


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## smokinj (Jan 26, 2011)

dannynelson77 said:
			
		

> This chart was just recently updated and all figures where downgraded a little.  Would like to know the explaination as to why but I dont see it?  For instance They used to have Red Oak and White Ash at about 24 MBTU.  Now they are at about 22 MBTU.  Also, they now have Honey Locust higher than Black Locust.  It used to be vice versa.  And its almost like they just rounded numbers with so many woods being exactly the same MBTUs now.  They used to be more specific or exact with each type.  Just makes me question the vailidity of the comparison.  I know its just a guide but not sure why all the changes......



Wow good eye, have thought there chart was low before.


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## Battenkiller (Jan 26, 2011)

soupy1957 said:
			
		

> I'd be hard pressed to be able to call around and see if I could buy exclusively one preferred type of wood (say "Black Birch" for example, that has a very high BTU rating).



Soupy, you might be surprised.  I just got more black birch in one year than I've burned in the previous 25 years.  

Since I never had a lot at once, I never noticed just how powerfully it burns is a straight load.  One of our members here, Gyrfalcon, said he got a lot more heat out of his little stove with black birch than with sugar maple, and I paid attention.  When I asked what woods my guy was cutting, he said it was a mostly oak woodlot, red and white.  "Any white ash?"  "Not a stick.  There's some cherry, a bit of beech...  I got quite a few black birch if you like that stuff."   Ding, ding!  Ordered several cord.  That's a big bargaining chip, a lot of these guys are hard pressed to find somebody who wants even one whole cord.  I got two cord delivered, then the guy told me he didn't want to cut anymore because the black birch on this woodlot was super stringy and hard to split.  I told him that was too bad, because I really wanted all black birch like he said.  Well, don't I get a call the other day telling me that the guy has another load of black birch ready for me.  If the black birch availability stops... well, he still has that beech, ya know? ;-) 

Wood is a commodity, just like any other.  Supply and demand dictate the price and the quality.  The supply is always there, but the demand for green wood peaks in late summer/early fall.  These guys need to put shoes on the kids and food on the table all year round.  If they know you are ahead on your wood supply, they will often jump through a few hoops to get the business during slack time.  Always ask what they are cutting, you just might get what you want.  Most of these guys have picky customers that they don't want to lose.  Learn to be one of them and let them deliver the sopping wet red oak to someone else.


As far as the charts go, they are calculated by using the average density of each species when it is dry, then using the amount of chemical energy in a cord of wood at that density.  Nobody is out there actually measuring the heat output from a wood stove using these woods.  I feel that the charts are only a rough guide.  How each wood burns in the stove is the final determinant of heat output. 

For example, black birch is right about up there with black locust and shagbark hickory.  Of the three, the black birch burns fastest, the hickory is second, and the locust burns for a very long time... at least in my stove.  What that means is that the birch will put out more heat in a given time than will the locust, even though they all have close to the same BTUs in a cord.  Sure, that also means I use more of it in a given time, but the extra heat output per hour can make the difference between a comfortable home and a chilly one.


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## dannynelson77 (Jan 26, 2011)

Battenkiller said:
			
		

> soupy1957 said:
> 
> 
> 
> ...



I understand the calculation....just not why so many changes.  And why they rounded the weight for so many species of wood when it appeared to be actual weights before the changes.


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## jimbom (Jan 26, 2011)

I am so thankful for those that share information on the internet.  For someone like me, it often is the only way to get up to speed on different topics.  Wood is a good example.  It was burned when I was a  kid.  I burned it in one place I stayed in college and burned it in one place I lived overseas.  However, I never really knew anything about burning wood.  Today, 40 years later, a whole new world of wood technology and information is open to me due to the good graces of strangers.  Thanks very much to all.

That said, it is good to think about what is posted and why the numbers are changed etc.  It is also good to experiment with different information in a hands on way.  Often, I can not get the same results that I read on the internet.  So I don't build anything or spend much money, until I try it myself.  The prudent man rule is what one of my bosses called it.


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## Jags (Jan 26, 2011)

Another one for those of you that like to compare:

http://www.ianrpubs.unl.edu/epublic/live/g1554/build/g1554.pdf

And a couple more odds and ends links that may be of interest

Chain saw collecting: http://www.acresinternet.com/cscc.nsf/GasbyManufacturer?OpenView

Tree distribution maps: http://esp.cr.usgs.gov/data/atlas/little/


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## soupy1957 (Jan 26, 2011)

I find it interesting that you state that Black Birch burns up faster than Hickory, and yet gives off more BTU's than Hickory (or are they more or less equal, I didn't compare them in the chart provided).

I'd think the "harder" the wood, the longer the burn, the higher the BTU's.

-Soupy1957


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## Backwoods Savage (Jan 27, 2011)

Wait about 5 more years and the charts will change again. We must remember these things are guides and not exacts.


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## gzecc (Jan 27, 2011)

dannynelson77 said:
			
		

> This chart was just recently updated and all figures where downgraded a little.  Would like to know the explaination as to why but I dont see it?  For instance They used to have Red Oak and White Ash at about 24 MBTU.  Now they are at about 22 MBTU.  Also, they now have Honey Locust higher than Black Locust.  It used to be vice versa.  And its almost like they just rounded numbers with so many woods being exactly the same MBTUs now.  They used to be more specific or exact with each type.  Just makes me question the vailidity of the comparison.  I know its just a guide but not sure why all the changes......


This chart is probably maintained by a 18 yr old secretary that doesn't know a wood fire from a gas fire.  Or the person that maintains it adjusts it for his own (financial) purposes.  Man, am I cynical or what?


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## oldspark (Jan 27, 2011)

That chart is about as good as it gets, some are nuts.


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## wetwood (Jan 27, 2011)

They have expanded the list. It used to have 55 wood species now it has 70.


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## wetwood (Jan 27, 2011)

Here is their old chart for comparison.


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## Freeheat (Jan 27, 2011)

soupy1957 said:
			
		

> Unfortunately, since I don't cut down my own trees, or cut up fallen trees, I'm at the mercy of the guy or gal I choose to buy from.  Typically, a wood load will have a mix to it.  Some very desirable woods will be in it, and then again, perhaps not so much so.  I'd be hard pressed to be able to call around and see if I could buy exclusively one preferred type of wood (say "Black Birch" for example, that has a very high BTU rating).
> 
> Would I LIKE to get the most BTU's out of my wood that I'm burning?  Sure............
> 
> -Soupy1957



Soupy we have a grain store in Ohio that ony sells oak, cherry, and hickory as a blend , maybe there is something arround you. BTW it ain't cheap but seasoned for over one year


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## jebatty (Jan 27, 2011)

Regardless of any changes, which logically would be related to more uniformity in what "dry" or "seasoned" means or in what flue temp is considered the standard, the more interesting number is lbs per cord. 

The cord itself is highly variable, as we all have found out. But lbs is a fact, and within a narrow range all wood has the same btu output per pound. In this chart that number is right around 6200 btu/lb and is based on 20% MC and stack temp of 300-350F. I have been using a different number, 6050 lbs/cord, which is derived from 20% MC and 400F stack temp. 

With my gasification boiler, I have center of flue temp of 380-430F (about 200F on surface of flue 18" above flue collar). With my wood stove, I have 300-350F on surface of flue 18" above flue collar (about 600F center of flue). My wood is well seasoned and likely is at 20% or somewhat less. Based on my flue temps, I consider the 6050 btu/lb more accurate in my particular situation.

For those who burn less seasoned or green wood, consider that you will burn 2-3 times the amount of wood to get the same heat value as 20% MC wood.



> It is also useful to note how these concepts apply to un-seasoned (green) wood fuel. If only seasoned a short time, 50% moisture is a realistic figure. Then a two-pound piece has one pound of wood fibers (worth 8660 Btu). There will be 1.54 pounds of water to vaporize and heat up (taking away 2200 Btu). The two-pound piece has a net available energy content of 6460 Btu or 3230 Btu/pound. This is only HALF of the available energy present when burning seasoned wood. Green wood consumes the bulk of its energy just to keep itself going, and is obviously subject to easily going out.
> 
> A freshly cut tree has even higher moisture content, often above 60%. Similar calculations show that this fresh wood has only 2000 Btu/pound of energy available. This explains why it is so difficult to burn freshly cut trees.


 Energy in Wood


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## amellefson (Jan 29, 2011)

Just came across that site this morning. One of the most thorough charts I have seen. You beat me to the post. Nice work.


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