The Science of Seasoning

I conducted a bit of an experiment on some oak that was knocked down in June of 2017 by a tornado.
I cut the tree into rounds in April of 2018 and opened a round in January of this year. Lots of water
in the split round, and my meter said 20 % moisture. My experimental piece of wood weighed 33 ounces on the 6th of January and 20 ounces by the 28th of February. In less than two months it had dropped 13 ounces of water weight, and now read 5% moisture on my meter. I dried the piece of wood in my front porch,
which has good southern exposure, and glass windows. Sorry for the long story. My point is this:
green wood takes a lot longer to dry than downed timber. Does anyone know why, is the moisture held
tighter by the cells? I think its more than the quantity of moisture. Comments please.

Thanks

Lepus

 

Welcome aboard Lepus


Sitting in round form, unsplit there's not as much surface area for the moisture to escape.

I'm kinda surprised how quickly it lost the moisture once split though.

The 5% reading, was that taken on a fresh split internally?

Remember, it may be dry surface-wise, but not internally.

Green wood would/should naturally take longer to dry than previously felled/bucked wood, as it would be containing more moisture.

But in log form, it really won't dry out much.

 

couldnt have said it better myself. Two thumbs up Chaz

 

Hello Lepus and welcome to the forum! . Bunch of great folks and knowledge here!
Cant say for sure if it dries faster when cut green or from cut down/fallen tree.
My questions to you: What was the size of the split when you took the moisture meter readings? Was it "fireplace/stove" size?
Case in point. I scored this deck of cut trees that is maybe two years cut. Most of the bark falls off easy when bucked. The internal moisture seems the same as a fresh cut green tree. I have a meter and didnt put it to the fresh cut logs. Just bought it in March and havent used it a lot.
Did you split the piece and take the reading as Chaz stated?
Pic from a month ago. The logs were stacked off the ground. It is mostly red oak. I personally would not burn this until the 2020-21 season at the earliest. The red maple and birch may be ready for upcoming Winter. Ive been CSS (cutting, splitting, stacking) on site.
Ive always preferred fresh cut green wood, but since ive been a member here im starting to like the barkless approach and find myself removing bark when it is easily done. This will speed up the drying process. I still personally prefer fresh cut "green & clean" wood.
It would be an interesting experiment to season a fresh split green and fallen/sitting side by side and see the results.
the deck when i left on Sunday.

 

green wood takes longer to dry than wood that has had a head start drying ?

There's free water and bound water in wood. Usually, the bound water takes longer to "evaporate" as it is chemically bonded to the cells. Free water level can rise and fall with the humidity level in the environment.
Which is why standing dead can often "season" so fast as the bound bonds were broken a long time ago and only has to give up the free water which can be achieved rather quickly.
5% moisture content is rather difficult to achieve without a kiln and even then won't stay at 5% once put into the humid environment and will swell in the Summer taking on moisture and shrink in the Winter releasing it. Wood, being hygroscopic will equalize and follow the relative humidity and temperature of its environment.

 

Welcome Lepus ! I did a bit of an experiment last winter with some rather large oak splits and a makeshift indoor kiln. I baked the wood at about 140 deg for days and gave the splits a massive amount of airflow. After the first few hours you could see water seeping out onto the floor from all the moisture that oak was giving up. After a week or two I took the wood out and re-weighed many test splits. Some of the 8-9 lb splits lost over a pound of water! Moisture readings from the ends and sides of the splits measured in the 5-8% range (down from 20-30% pre kiln). I was so excited and thought I finally had some big dry oak splits to throw in my stove!!! Or so I thought. After tossing in a few of these “dry” splits I noticed they burned beautifully for about 20 min and then they would nearly become extinguished and just smolder in the coal bed of the stove. This is when I learned that to get accurate moisture readings u must first split the split and take a fresh reading from the inside. When I did this with my “kiln dried” oak splits I found that while the outside of the splits was really 5% the inside of those oak splits was still 25%!!!!! The kiln barely even made a dent in that oak. Now silver maple and ash were another story. They cured beautifully through and though after a week in the kiln. I guess I just had to prove it to myself that with oak there is no shortcut to the three year plan. That said I have still been thinking of trying the kiln again this year maybe with an external dehumidifier... I guess I’m a slow learner! Anyway sorry for the long story but I thought it might be helpful.

 

Neat!

 

what was the end size of the oak splits prior to kilning? My splits are roughly the size of a 4x4 or 3.5"x 3.5", give or take.

 

I just grabbed a piece of cut, split and stacked oak that's been split and stacked for 2.5 years in a sunny area.

I measured the end, side and then split the piece in half to get an internal %.

 

Here's a piece of mulberry that's been cut, split and stacked for 25 months. Same deal, end, side then internal %. Also include a pic of my stacks.

 

Forgot I had some 2 year cut, spit and stacked pine. This got me through the 2017 winter. I moved in late 2016 so I didn't have much seasoned firewood on hand. I started burning it when it was 6-7 months split and seasoned. IIRC it was around 20% on avg after 6 months. It burned well enough and help subsidize the small amount of seasoned hardwood I brought with me during the move.

 

Welcome to the club. Lots of great folks on here, sharing knowledge and humor. We like pictures of saws , stacks, equipment, pets....
I think you will like it here...

 

I’d say on average my kilned splits were of similar size around 4x4”. This split I’m picturing here is 3.5” x4.5” x 20”. Just re-weighed it and it’s reading 8 lbs, 7.5 ounces and exterior moisture reading around 7%. It’s been in the garage all winter/spring but not actively kilned since 11/7/18 according to my notes. Lol. As u can see this particular piece was kilned for about a week and a half back in October/Nov. during that week it dropped about 10 oz. and exterior moisture reading went from 20% down to 7.5%. Maybe I’ll split it in half one of these days and check how it’s coming along on the inside. Any guesses as to interior moisture %????

 

Another test split.... each one has its own story....

 

So, YOU have my r/h glove, eh? Oh, never mind, one of the dogs just went by with it.
It'd be great if you resplit one of those bad boys and checked it. I'll bet it's more than 1%.

 

I'm going to guess 12%

Do you have a pic of your indoor kiln set up?

 

I remember dad had us c/s/s'ing log loads of wood in the late summer/fall then burning them through that same winter.
I also remember a couple of really good flue fires from the build up of creosote...


"No shortcut" is right.
...Thats why I try to stay 4 years ahead. as 90% of my wood is red oak...and since Pa is a tropical state.

 

Doing it by weight is the gold standard of measuring moisture content. The meter isn’t giving and accurate reading: if a 33oz piece of wood can lose 13 ox of water, it was clearly more than 20% water to begin with. The meter is correctly showing that the wood is dryer after 2 months, but the absolute values given by the meter are off.