Equilibrium Moisture Content of Wood in Outdoor Locations

I found this of interest:

https://www.fpl.fs.fed.us/documnts/fplrn/fplrn268.pdf

This publication seems to give the best one could hope for when seasoning firewood based on where you are located. With my knowledge of psychrometrics (properties of moist air) I wondered what the relationship was with temperature/relative humidity outside when you try and season wood.

Using my closest location (Baltimore MD) it looks like the best I could do is 12.8% in August.

Here is a graph:

Equilibrium moisture content - Wikipedia

If nothing else maybe this shows the best you can hope for when seasoning wood in your area.

Any thoughts or comments?

 

In north Europe it seems impossible to dry it below 18-19 % mc in the winter months but in US it looks like 12-13 % is possible.

So I believe that's a big reason we in Sweden only talk about one or maybe two springs to let firewood dry. Its possible to get it to that mc in one year.

 

I’ve learned I should ship all my Ct oak to Arizona for a long summer vacation

 

Cool info. In coastal CT, the lowest I’ve seen on a fresh split of wood was 16%. This was on a small split of locust about 8 inches long. I mostly see about 18% for my split wood. I always like videos where you have some guy with a moisture meter getting readings of like 9%. Something definitely off there.

 

I have some Oak under Black rubber roofing which I'm interested to see how long it takes to season.

 

Very interesting information SteveWest i posted a question about wood equilibrium awhile back. The table at the bottom really sums it up. I always wondered when it became a waste of time to let wood season any longer. Looks like for me (being from SD) Getting in the teens is about as good as it’s going to get. Now it’s time to get a moister meter .

 

The table at the bottom should go in the FHC resources section.

 

Good thinking...
Eric VW ...

 

Unless you can get it 15-30°F above ambient outside air temperature.

IE.. Solar kiln

 

Oh I dunno...we can use it to prove that you can't get to 7% in northern OH, like newbs sometimes try to say that their new moisture meter is showing them when they stick it into the end of an unsplit round...

 

Exactly.

Then it bakes out the moisture.

 

Maybe that would be cheaper to do than using a kiln to dry the wood. ;-)

 

Well when you heat air without a source of humidification it causes the relative humidity to decrease. Lower relative humidity is what you want to dry wood.

The issue you have is the humidity that is generated by the wood drying causes the relative humidity to increase. To get rid of the humidity you then need to ventilate the solar kiln which will cause the temperature to decrease.

Thus ideally what you need to do is find the happy medium of only ventilating so much to find a "sweet spot" for drying the wood.

What I have read online so far is that there isn't that much value in a solar kiln (like a green house) to try and dry wood.

 

That's really interesting! Thanks for sharing the link. I did have to chuckled that for New Hampshire, they picked Mt. Washington. I have a feeling firewood would season pretty well up there with the winds....if you could keep it from blowing away!

It's neat to see the variations in the different months for moisture levels. Certainly another reason to split and let it season for at least a year to get the maximum benefit of drying out.

 

No linky...

 

Eric VW I did go to resources at the top and I found it. It took a few clicks to get to the chart, but it is there.