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Firewood age

Started by jargo432, February 16, 2015, 09:05:18 AM

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jargo432

If you store your firewood in a barn, How long before it starts to dry out too much to get the most heat out of it?

Jack of all trades.

beenthere

QuoteHow long before it starts to dry out too much to get the most heat out of it

It can't dry out too much to get the most heat... the drier the better.

Just that real dry burns fast and some don't want their wood to burn fast, as then they have to add more wood sooner. Has more to do with controlling the burn time than extracting the most heat (i.e. BTU's) as I see it.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

jdonovan

also the faster burn rate of VERY dry wood can be a problem for some firewood burners as there will be more heat than they were designed for.

Unless you are in a very arid environment, wood stored outside, will generally be in the 10-20% range, and should work fine in most wood stoves.

pineywoods

I store my firewood in the barn, for up to 2 years. It don't get too dry. If your wood burns too fast, you need to cut back on the air supply.
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

Jhenderson

The university of Maine disagrees with you fellas. They claim ( if I remember correctly) that wood that is left to dry for too long a period looses BTUs. Seems as though wood distills an alcohol. Dry too long and the alcohol disappears. The alcohol adds BTUs. If I remember correctly they said 10-12 months for mixed northern hardwood, a little more for oak. I agree with them. Burn sound dead stand oak against 1 year seasoned oak and you'll easily see the difference. That's why I won't sell dead stand wood. I feel as though I'm doing a disservice to my customers if I do.

jdonovan

I'd be curious to see the original study/research. Do you know if its online anywhere?

searched but could not find it.

bandmiller2

The amount of moisture in wood depends on the ambient humidity, down where ole Piney lives the wood won't be as dry as say Maine in the winter. Its always been said ideal is to stack wood outdoors to dry for a year then stack it in a dry woodshead for another year. Most of us do well to cut it this winter to burn next. Frank C.
A man armed with common sense is packing a big piece

beenthere

I'd be interested in the U. of Maine report that you mention.
Wood cannot reach zero moisture content, but can only approach it - no matter how long left to dry (as long as decay doesn't set in as then one will lose BTU's per volume, not per pound).

Here is what I found for a chart http://www.mha-net.org/docs/v8n2/docs/WDBASICS.pdf



 
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Ianab

I can see where standing dead wood might loose some BTUs because decay starts while the wood is still sound. So Jhenderson's practice of not selling standing dead firewood probably has merit. The wood may not be quite as good as the fresh stuff.

But once the wood is "Dry" (under ~20%) then any decay should stop. As long as it stays dry and doesn't get eaten by bugs, it shouldn't degrade for many years.
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

Warped

Early fall I diced up about six face cords of standing dead the power company dropped on my road frontage. I just got into it last week and sold my cabin tenant two cords to get him by (part time burner, lives alone). Well, asked my wife what she thought of it, not much of an opinion. I noticed while it throws very good heat it was seeming to burn slightly quicker than we're used to, but I'm infamous for burning green, probably more than I should. He stopped up today to pay me and commented that it burned quick before I mentioned it. I told him I'd run some more down to make up for it........It's solid with no degradation but may be a smidge light. Now, I'm embarrassed to say I'm not sure what it is but believed it to be ash but looking at it now I'm thinking white oak. Just not sure as the bark appears to be lighter brown in color than I'm used to and not sure the bark is as deep as my usual ash. Don't laugh at me! :laugh: ;D :laugh:
Good with the rough stuff and rough with the good stuff

LeeB

'98 LT40HDD/Lombardini, Case 580L, Cat D4C, JD 3032 tractor, JD 5410 tractor, Husky 346, 372 and 562XP's. Stihl MS180 and MS361, 1998 and 2006 3/4 Ton 5.9 Cummins 4x4's, 1989 Dodge D100 w/ 318, and a 1966 Chevy C60 w/ dump bed.

Weekend_Sawyer

Post a picture of the bark. I'm sure someone here can let you know what it is.
Imagine, Me a Tree Farmer.
Jon, Appalachian American Wannabe.

Warped

Quote from: Weekend_Sawyer on February 18, 2015, 05:42:21 AM
Post a picture of the bark. I'm sure someone here can let you know what it is.
I'm going to try, my puter's aren't cooperating, I'm on the last laptop, the kids.
Good with the rough stuff and rough with the good stuff

WH_Conley

I had a bit of Red Oak that had been in the barn for several years that I found when I cleaned it out. It was full of very small bug holes, had to drop it to knock the sawdust off. I burned it in the stove in the basement. I do think the flame was cold. :( I do like to have my wood 8 months to a year old for the Papa Bear.
Bill

Ianab

Could be the bugs ate some BTUs ?  :D

Actually, seriously bug poop will have less BTUs. This isn't about the wood being "too dry". It's about it being 1/2 digested by bugs.  :D  And yes that can be a problem with the long term storage of some types of wood.
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

bandmiller2

There are finer points to fire wood and BTU content, this winter the biggie is "enough". I have always coveted dead standing especially good elm, tough on the chain though. Frank C.
A man armed with common sense is packing a big piece

landscraper

Quote from: jdonovan on February 17, 2015, 08:57:35 PM
I'd be curious to see the original study/research. Do you know if its online anywhere?

searched but could not find it.

X2

I'd be very interested to read that study.  To be clear, dry wood means something entirely different than decomposed, rotted or otherwise degraded wood.  If you are losing mass due to degrade you are certainly losing BTU's.
Firewood is energy independence on a personal scale.

jdonovan

I did some more searching and found several other articles/studies by U M Orono, and they all seemed to indicated dryer wood had more available BTU's. Found no references to older wood having less heat content than newer wood when they were both at the same moisture content.

beenthere

south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

drobertson

I followed some guide lines years ago on the available btu's in differing wood types.  None of which discussed the burning of standing dead timber.  I too harvest a fair share of standing dead red oak at times, and have found the heat produced is adequate for certain, but it does seem with my very non scientific study that it does burn much quicker with less coal retention.  For me wood is wood so long as it's dry.  But If I had my druthers I would prefer a good air seasoned and split white oak, the post oak being close to tops for burn time and BTU output.
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

tim in New York

Wood can definitely get too dry if you leave it under cover for several years.  I've had a few piles that got stuck in the back of my wood shed for a couple of cycles.  I cleaned one of them out last year, and about half of the pile was like balsa wood.  It was good quality when I put it away 4 or 5 years ago.

Tim

beenthere

Quote from: tim in New York on March 05, 2015, 09:46:53 PM
Wood can definitely get too dry if you leave it under cover for several years.  I've had a few piles that got stuck in the back of my wood shed for a couple of cycles.  I cleaned one of them out last year, and about half of the pile was like balsa wood.  It was good quality when I put it away 4 or 5 years ago.

Tim

Then it had to have gotten wet while stored there, or never was able to dry in the first place.

Don't think it was from getting "too dry".
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

SLawyer Dave

The "balsa wood" issue is most likely due to one of a number of powder post beetle infestations.  When the cut and seasoned wood is stored for long periods of time under a roof, then the wood gets so dry with the interior wood exposed, that the powder post beetles just love it.

For btu value, some moisture in the wood is optimal, (I've been told 8-10% but I don't know if this is accurate).  If the moisture level is too low, then the wood burns very fast and the "moisture" in the wood is not present to get heated up and thereby give off additional btu's. 

LeeB

The  moisture will not give of any BTU's. It can only consume BTU's while being converted to steam.
'98 LT40HDD/Lombardini, Case 580L, Cat D4C, JD 3032 tractor, JD 5410 tractor, Husky 346, 372 and 562XP's. Stihl MS180 and MS361, 1998 and 2006 3/4 Ton 5.9 Cummins 4x4's, 1989 Dodge D100 w/ 318, and a 1966 Chevy C60 w/ dump bed.

jdonovan

Quote from: SLawyer Dave on March 08, 2015, 12:05:07 AMFor btu value, some moisture in the wood is optimal, (I've been told 8-10% but I don't know if this is accurate).

You were misled.  0% ZERO moisture is maximum BTU value. If there is any water in the wood it needs to be removed before the wood can heat enough to offgas, and burn. That hot water vapor carries heat up the chimney that never gets to heat things you want to heat.

QuoteIf the moisture level is too low, then the wood burns very fast

true

Quoteand the "moisture" in the wood is not present to get heated up and thereby give off additional btu's.

false

There is some round-about truth hidden in the above.

Because in the real (non lab) world no one has 0% MC wood. Unless you try REALLY hard, or live in a desert, no one even has 10% MC wood if its stored outside. Therefore wood burning appliance manufacturers have to design their products to work well with wood in the 10-25% MC range.

If you put 5% mc wood into a burner optimized for 15% wood, then you get more gas off the wood than the appliance can burn, and you fail to capture all the BTU's that are in the wood...and the wood burns faster than the 15% and the end user perceives the wood burned up faster, and therefore had less heat.


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