Need FACTS on wood drying times

[cottonwoodsteve]

Battenkiller says it evaporates from the end 15 times greater than the side grain. He did not say nothing evaporates from side grain.
If you take a clear piece of plastic and cover a few week old split, the plastic will immediately fog up in the shape of the triangular end but absolutely no moisture shows on the side. I can't tell if it is 15 to 1 but it is a very dramatic difference in the early stages of drying.
So Battenkiller's info and my experiments show that splitting may not be as important as people think. Does it help, yes, but not that much. There may be conditions where cutting a small round a few inches shorter may be even better than splitting a longer piece. Just speculating here.
But then there is still the transport problem. So most will need to split no matter what.

Lot's of good info coming in. We may all learn something.

I think what was bothering me was making blanket statements about wood drying is like making blanket statements about planting corn. When should I plant corn? In the upper Mid West planting time is mid May. In some part of the South West mid May is called harvest time, before the dry heat kills everything.

 

[jimbom]

...When should I plant corn?....

I know this one:

Plant your corn when oak leaves are the size of a squirrel's ear. Works everywhere.

 

[cottonwoodsteve]

Interesting, I will have to pay attention to the size of the oak leaves this spring . It may make sense and automatically adjust for that exact years weather.
Most big commercial farms in California are in areas that don't have Oak trees. So that's why it may not be a common saying here.

We are learning a lot here!

 

[jebatty]

Interesting discussion but doesn't really help much to get my firewood dry. Cut, split, stack, cover with corrugated steel allowing air flow, wait two years -- ready to go.

For the FACTS, need precise, by the minute, daily temperature, humidity, wind, cover; then this is impacted by each split, proximity to other splits, mice buidling nests in the stacks and blocking air flow; then the precise dimensions of each split, knot content, species, bark cover, surface texture; then add in all other known and unknown variables; then need to pull each split from the stack when the facts show that it has reached a target moisture content -- might be better to wait 2 years, drink beer, and cut some more wood for year 3.

 

[Battenkiller]

Interesting discussion but doesn't really help much to get my firewood dry. Cut, split, stack, cover with corrugated steel allowing air flow, wait two years -- ready to go.

For the FACTS, need precise, by the minute, daily temperature, humidity, wind, cover; then this is impacted by each split, proximity to other splits, mice buidling nests in the stacks and blocking air flow; then the precise dimensions of each split, knot content, species, bark cover, surface texture; then add in all other known and unknown variables; then need to pull each split from the stack when the facts show that it has reached a target moisture content -- might be better to wait 2 years, drink beer, and cut some more wood for year 3.

I don't think Steve is asking for that kind of precision any more than a farmer needs to know exactly when to plant each particular corn seed, or how deep, or how much water it needs each minute, ect. He is just looking for a less generalized way of quoting drying times.

In other words, why wait 2 years for your wood to dry when you know it will dry to 20% in your climate in about 3 weeks?

 

[Battenkiller]

Lord, I thought the world as I knew it was coming to an end. Thanks for clarifying BK. When you said that wood dries faster through the ends than through the "sides" I thought you meant the inside split sides, rather than the bark.

Sorry to disturb your future sleep, but that is exactly what I meant. Yes, it has been shown that boards dry 10-15 times faster through the end grain than through the lateral faces. Every kiln operator and lumberman in the world knows that fact, why should wood behave differently just because you cut it short and split it?

The primary reason why split wood dries faster is that by splitting it you expose more surface area.

For example, take a 24" round that is 18" long and strip it of bark to expose the bare wood. It has an outer surface area of 1357 sq.in. on the sides of the cylinder and 905 sq.in. on the ends. If I take the low figure of 10X the drying rate from the ends, this round will lose about seven times as much water from the ends as it does from the sides.

Now split it in half. You have increased the lateral suface area by 432 sq.in. Split those halves and you gain another 432 sq.in. of drying area. Split those in half and you gain another 864 sq.in. You still have the same surface area exposed on the ends, but you now have 3 1/2 times the lateral surface area that you started with.

Then you have to consider the diffusion of water molecules across the grain. In the round, a molecule of water in the center had to travel 12" to gain freedom into the surrounding air. In a 4" thick split it only needs to travel 2".

So there are at least two important reasons to split wood to increase the drying rate, but it will always be that for a given surface area water will leave the wood 10-15 times as fast as an equal size surface area on the sides.

 

[SolarAndWood]

With the bark on, is it effectively 0 from the sides? Does that explain why you sometimes see sizzle between the bark and wood of what otherwise appears to be a dry split?

 

[krex1010]

Asking how long it takes to season wood is like asking how long to BBQ a pork shoulder, the only reliable answer is , it's done when it's done. There are so many variables that affect the season time, temperature, humidity, wind and sun exposure, species, split size. There are no hard facts, it's seasoned when it's seasoned, and even defining "seasoned" is up for discussion. Thats why we go by general rules, under most conditions and most species, split and stacked with room for good airflow and good sun exposure, a year in those conditions will generally give good burning wood. There is no recipie, if you need a recipie, bake a cake, or heat with oil Lol happy burning!

 

[Battenkiller]

With the bark on, is it effectively 0 from the sides? Does that explain why you sometimes see sizzle between the bark and wood of what otherwise appears to be a dry split?

Effectively zero? I don't know about that, but I suspect it is a lot slower. What you see coming from between the bark and sapwood might also be rain water that wicked underneath the loosening bark. Of course, I know that you season your wood in a shed, totally protected from the elements. ;-P

 

[benjamin]

If Steve hadn't noticed, the members of this forum are concentrated in the Northeast, and the Midwest. Our climate conditions and woods are similar enough that rules of thumb are close enough. Most of us don't cut a lot of Eucalyptus.

Also, you'll notice that there isn't a forum dedicated to air conditioning on this site. Air conditioning is a way of life in some parts of the country. For most of us, the lack of air conditioning would mean a week or two of discomfort most years.

Of course this doesn't answer any of your questions, but here are some tips that might help you figure out whether you need to pay more attention to your wood drying process.


If your neighbors own snow plows, then you might need to worry about drying your wood.
If your neighbors own swamp coolers then you probably don't need to worry about drying your wood.

If you know precisely how long it takes for your wood species to get "punky", then you just might need to worry about drying your wood.
If you cut wood species known for fueling catastrophic wildfires, then you probably don't need to worry about drying your wood.

If most of the birds you see can swim, then you might need to worry about drying your wood.
If most of the birds you see go "bee-beep" and have legs that turn quickly in a circle while running from coyotes dropping anvils, then you probably don't need to worry about drying your wood.

 

[SolarAndWood]

What you see coming from between the bark and sapwood might also be rain water that wicked underneath the loosening bark. Of course, I know that you season your wood in a shed, totally protected from the elements. ;-P

lol, I'd buy that. I'm not sure I have ever seen it from splits from the shed, just splits that come direct from the heap. If it weren't for snow and ice, they would all come direct from the heap :coolsmirk:

 

[jimbom]

...some tips that might help you figure out whether you need to pay more attention to your wood drying process...

:lol: Classic.

How about: If your landscaping is succulent and stone, you don't need to worry about drying your wood.

 

[jatoxico]

Battenkiller says it evaporates from the end 15 times greater than the side grain. He did not say nothing evaporates from side grain.
If you take a clear piece of plastic and cover a few week old split, the plastic will immediately fog up in the shape of the triangular end but absolutely no moisture shows on the side. I can't tell if it is 15 to 1 but it is a very dramatic difference in the early stages of drying.
So Battenkiller's info and my experiments show that splitting may not be as important as people think. Does it help, yes, but not that much. There may be conditions where cutting a small round a few inches shorter may be even better than splitting a longer piece. Just speculating here.
But then there is still the transport problem. So most will need to split no matter what.

Lot's of good info coming in. We may all learn something.

I think what was bothering me was making blanket statements about wood drying is like making blanket statements about planting corn. When should I plant corn? In the upper Mid West planting time is mid May. In some part of the South West mid May is called harvest time, before the dry heat kills everything.

I personally have learned nothing new that has not already been covered here at length. The only blanket statements I heard were made by the OP.

 

[Battenkiller]

lol, I'd buy that. I'm not sure I have ever seen it from splits from the shed, just splits that come direct from the heap. If it weren't for snow and ice, they would all come direct from the heap :coolsmirk:

And that BBK would just eat up that sizzle like it was an aperitif. ;-)

BTW, rumor has it that your heap is almost all the way to Saratoga by now. If it gets any bigger I'm gonna start sneaking some splits off you in the middle of the night. :lol:

 

[SolarAndWood]

BTW, rumor has it that your heap is almost all the way to Saratoga by now. If it gets any bigger

I'm on cruise control now that I know how long it takes to dry bigger splits in the heap with reasonable certainty and am far enough ahead to maintain it. For my situation, that is 30-40 cord. For the OP, it sounds like it is more like half a cord.

 

[pdxdave]

I've noticed a general trend where anytime someone posts a thread asking for some real specific drying information, it's because they have a pile of wood that's been split for 4 months that they want to start burning next weekend and need forum approval.

 

[cottonwoodsteve]

pdxdave
I am not looking for approval for a quick burn.
What I am looking for if facts. I am trying to figure out why everybody keeps saying I need multi year drying times, and split some exact size. I want to know what is the advantage of all of this.
If you remember the rule even doctors said for the last 100 years. Never go swimming within one hour of eating lunch or you will get sever musclel cramps. Recently some research group studdied this. There was no original test data to be found and their experiments could not produce the cramping results. I wasted a lot of time in my youth because if this "old wives tale". Basically I don't want to split and dry exact times and methods unless I know why and what is the real results.

Summing up BK heavy math brought up a point I did not think of.
His data and my experiments say nothing much comes out of the sides % wise.
In simple round numbers, ten times more comes out of the end than the sides per square inch.
But the sides may have 10 times more square inches of surface area.
Or another way of looking at it, the sides don't emit much moisture per square inch but the sides have lots more square inches of area.
Excellent info. I just never thought in emissions per square inch.

Splitting a large slit in two increases the side area but the end total is still the same. So therefore it will dry much quicker because even though the sides don't emit much per square inch, you just doubled the side area.

So splitting speeds up the drying time. Splitting in smaller pieces speeds it up even faster.

Now I am making an educated guess here;
Long multi year seasoning times probably are not too sensitive to exact processing time to exact burning time. In a real short time I thingk exact times are more important.
If I cut and split in June it is very hot and dry.
My wood is ready to go in 3 months easily. Actually probably in 3 weeks!
If I cut and split in November, cold damp and rainy, it might take 8 months or more because nothing will really start drying until spring.

Question for JimboM;
For the corn planting part, I can measure the emerging Oak leaves but how do you get a squirrel to stand still to measure his ears :>)

 

[krex1010]

I don't believe you need multiple years to season wood, generally speaking. If stored properly and split size isn't extremely large then if you give your wood 12 months you are generally in good shape, you may not be at 15% mc, but you should be at least close to 20% which I think is burnable. There are exceptions to this but I have oak that is about 22% mc , that seasoned for a little over a year, and if I need it I'll burn it this year, and it will burn fine . There are no facts or procedures that will work for everyone in every situation.

 

[Battenkiller]

For the corn planting part, I can measure the emerging Oak leaves but how do you get a squirrel to stand still to measure his ears :>)

Put out some corn for him.

 

[Battenkiller]

BTW Cottonwood, I like your avatar photo. Been there, done that. Actually, 'twas my first experiment. :coolcheese:

 

[jebatty]

cottonwoodsteve: I am not looking for approval for a quick burn.
What I am looking for is facts.... If I cut and split in June it is very hot and dry.
My wood is ready to go in 3 months easily. Actually probably in 3 weeks!
If I cut and split in November, cold damp and rainy, it might take 8 months or more because nothing will really start drying until spring.

If you are looking for facts, and if you think you have found them in these posts, then you're not reading very well. Perhaps your best source of information will be your neighbors who burn wood, as they live in climatic conditions most similar to yours. Obviously, since mine is northern Minnesota, where I live there is not a single fresh cut tree that ever would be ready to burn in my wood stove or in my gasifier in 3 weeks, and I haven't found anything that would be ready in 3 months of hot, dry weather. Good luck to you in your search for facts. For me, I will cut, split, stack, cover, and burn in two years. And that's a fact.

But since you already know that if you

cut and split in June it is very hot and dry [and your] wood is ready to go in 3 months easily. Actually probably in 3 weeks!

, then why bother asking for any more info from the well meaning people in this forum. It is obvious you already know everything you need to know about drying wood. Keep the home fires burning.

 

[Backwoods Savage]

Methinks it is best I stay out of this one. I could tear it apart too much and start something nasty.

 

[cottonwoodsteve]

I think benjimen brings up a good point.
Most of the people in the forums live in areas were the weather is all the same and the wood is all the same.
The temperatures, humidity, and snow vary relatively little across the whole area.
You family has lived there for generations and developed it's own wood cutting and drying methods over the years.
It is sacrilege to question it and it probably really works great.

Anything Denver and west has a much great weather and wood differences.

There are a lot of people in the west that burn for heat but I guess they are not the type that join forums.

50 miles south it never snows. Here we get a dusting of snow once in the winter. 50 miles east they get 30 to 40 feet! Very different wood drying weather.
And the wood in the state varies just as much.
Most on the forum burn Oak, Maple etc.
Here we burn Oak, Eucalyptus, Pine. In some of parts of California they burn Avocado, Almond and Orange.

Chimney fires are never a problem because earthquakes knock down the chimney way before the creosote ever builds up.
OK, I'm pulling your leg on that one.

 

[SolarAndWood]

There is a lot of variation here too. I would never get away with what I do at home at our camp. Home is on a windy open ridge, camp is in the middle of mature forest. Home dries in a heap, camp dries eventually stacked in an open sided shed.

 

[quads]

Methinks it is best I stay out of this one. I could tear it apart too much and start something nasty.

Yup!

For me, part of the fun of heating with wood is the simplicity of it.....cut, split, stack, forget about it for 2, 3, 4, or whatever years and then burn it. Most days there are far too many things that require a lot of thought, pieces of dead trees that I'm just going to throw in the fire eventually is not one of them.

But hey, to each his own! I guess ciphering and analyzing can be a hobby in itself.