Firewood storage life?

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sirlight

Burning Hunk
Dec 4, 2021
114
Albany, OR
Never a bad thing to be way ahead on my firewood but I am out of space to store more inside the barn. I have stacked a few cords outside now on pallets. The top of the row is covered by used metal roofing panels, but the sides are still exposed to the weather. I can continue to process firewood since I have very easy access to tree service logs now. Question is, when wood is stored outside with some weather exposure, can the wood be unusable for burning at some point? I am currently almost 7 years ahead.
 
At some point yes, for some species of wood. Alder, for example, breaks down pretty quickly but I have 5 yr old madrona and cherry in the shed and it's fine. I think 7 yrs is a bit much for this area. Doug fir seasons well in 6 months if top covered. After that its internal moisture seems to stabilize at around 17%.
 
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I've burnt 20 year old oak that burned great. I've burned 2 year old birch that was a sponge. Both were split and stacked. Really depends on species.
 
I’ve seen 15+ year old firewood that was stored in a barn. It burned just fine. If that same wood had been stored outside though, who knows.

Firewood is the same as lumber, it’s all in how it’s stored. I’ve been using some air dried pine boards that my dad had sawn up when I was a kid 35 years ago. It’s been on stickers in his barn since then. Like begreen mentioned, once it reaches a certain MC it will stay right around that number.

I say build more wood sheds if you can. Or burn the wood in the shed and then continually rotate the wood stored outside into the shed.
 
If its up off the ground, protected from splashing and covered it will last decades in typical environments. Look at old barns and farmhouses, as long the roof is good they least a long time, once the roof goes, the clock is ticking. That said, there is some degradation in btu content over the long term. The cellulose content is pretty stable but the wood alcohols and heavier volatiles tend to slowly "cook off".

Ideally, sell the excess wood and convert it into cash then invest it.
 
I was reading a thread in the wood furnace section where they were talking about wood being too seasoned, and if that’s possible.
I think that all depends on where you live. I know in upstate NY I don’t have a problem with wood getting too dry. But if you lived in a very dry place then maybe.
 
I was reading a thread in the wood furnace section where they were talking about wood being too seasoned, and if that’s possible.
I think that all depends on where you live. I know in upstate NY I don’t have a problem with wood getting too dry. But if you lived in a very dry place then maybe.

If your humidity never drops below 15% (like on the east coast) then your wood can not get lower than 15% moisture (excluding kiln dried). Even if your wood was kiln dried to 5%, if it sits around in 20% humidity the moisture content of it will rise.
 
Some people stretch burn time by using partially dried wood t stretch the burn. Its definitely not a great idea as that extra moisture is taking BTUs up the stack. A modern air tight design should not be impacted by very dry wood.
 
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If your humidity never drops below 15% (like on the east coast) then your wood can not get lower than 15% moisture (excluding kiln dried). Even if your wood was kiln dried to 5%, if it sits around in 20% humidity the moisture content of it will rise

The warmer air is, the more water it can hold. The air humidity that we commonly use is relative humidity, where 100% is the maximum amount of water the air will hold at that temperature. This makes sense to us because it matches what we feel. Where with wood it's percent by weight. They're very different measurements. The equivalent wood moisture % is always less than the air RH. Equivalent being the equilibrium point, what wood left in those conditions will eventually dry to.

For example at 90 degrees and 50% RH, the equivalent (equilibrium) wood moisture is 8.9%.
See the chart on pg 3:

https://www.fpl.fs.fed.us/documnts/fplrn/fplrn268.pdf
 
Here is an equilibrium moisture chart by location, and month of the year too...interesting.
Edit, oops, I see that is what was posted above
Most species of wood will last almost indefinitely if its kept dry...not that it can't get wet at all, just stored in a way that it can dry out easily...up on a pallet and top covered works well for most...about the only fly in the ointment with that storage technique is if leaves and pine needles can fill in the gaps, or maybe critters building nests...that stuff can hold moisture and allow the wood in that area to decompose.
 
I was reading a thread in the wood furnace section where they were talking about wood being too seasoned, and if that’s possible.
I think that all depends on where you live. I know in upstate NY I don’t have a problem with wood getting too dry. But if you lived in a very dry place then maybe.
I just posted thsi below but maybe here is a better place?

"Desert Wood Burning or "Toto, I do not think we are in Northern Minnesota anymore"
Sooooo..... that said now while I figure out my Woodstove, part of my problem is wood that is TOO DRY! Huh? In northern Minnesota that was never a problem. Now I am learning my Beautiful Dead and down bone hard solid Oak I have been putting up has basically a 0% moisture content and it is causing massive creosote build up. There seems to be no free lunch anywhere. So some of my wood may reach 8-10% if I spend a lot of time checking so my question is how do I remedy the too dry/too green/ too wet wood issue? Spray it down? Leave it uncovered? Mix with hard to find greener wood? if I use a 0% MC (moisture content) piece of oak and a 25% MC.....any other desert rats out there that have hit this snag?"
 
I responded in the other thread.
 
I just posted thsi below but maybe here is a better place?

"Desert Wood Burning or "Toto, I do not think we are in Northern Minnesota anymore"
Sooooo..... that said now while I figure out my Woodstove, part of my problem is wood that is TOO DRY! Huh? In northern Minnesota that was never a problem. Now I am learning my Beautiful Dead and down bone hard solid Oak I have been putting up has basically a 0% moisture content and it is causing massive creosote build up. There seems to be no free lunch anywhere. So some of my wood may reach 8-10% if I spend a lot of time checking so my question is how do I remedy the too dry/too green/ too wet wood issue? Spray it down? Leave it uncovered? Mix with hard to find greener wood? if I use a 0% MC (moisture content) piece of oak and a 25% MC.....any other desert rats out there that have hit this snag?"
well yeah however there is plenty of talk about "Too dry of wood" I was told by a local desert climate woodstove/chimney expert that the other day and she told me that i have got to burn a variety of MC wood. Just saying. You did not answer the important part of my post about that.
 
Never a bad thing to be way ahead on my firewood but I am out of space to store more inside the barn. I have stacked a few cords outside now on pallets. The top of the row is covered by used metal roofing panels, but the sides are still exposed to the weather. I can continue to process firewood since I have very easy access to tree service logs now. Question is, when wood is stored outside with some weather exposure, can the wood be unusable for burning at some point? I am currently almost 7 years ahead.
I'm at 10 easily and if under cover preferably a building almost indefinite, look at the 200 year old barns scattered around the country the beams are perfect in many cases.
 
I don’t think firewood that is too dry would cause any creosote issues. That’s a wet wood issue only as far as I know. I mean I guess if you were completely smothering it or just building a smoldering fire maybe. But in “regular” burning, super dry wood just burns faster.
 
One of the byproducts of combustion, is moisture? Anyway -
I got hold of some wood that had been stored in a shed since 1975. Powder post bugs got at it so bad that half of it was lite and unusable. I had to use a respirator just to handle it. There was 6" of extremely fine powder by the time I reached the bottom. I threw it all out. 4 cords. Nasty stuff. Barn beams also may look sound, but those too can be eaten up inside.
 
Yes. Elementary chemistry. Hence the steam out of your tailpipe when it's cold. The hydrogen in organic compounds (as wood) reacts with the oxygen to form H2O.

A pound of zero pct wood gives about a half pound of water (I believe it was 0.44 pounds). Approximations present of course because not all wood contains the same amount of hydrogen atoms in its molecules.
 
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Have pulled Hedge posts from a fence that my dad and I put in in the middle 60's. Heaven knows how old they were when we put them in, but when I pulled some lately they were still as hard as rock. So hedge will probably out last me and the shed I store it in.
 
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I have burned wood that was in a barn for at least 30 years. It was dry, some powder, but still solid. The powder was probably what used to be the bark. Once I hauled it down the road at 60 mph, the dust was gone. Burned great. Still have to get the last load.