Seasoned versus Dry

[Gordon]

Here is an interesting piece I lifted from an article about drying wood for woodworking purposes. I'm still not convinced that letting a stave sit beyond the time necessary to properly dry imparts any special qualities to the wood.

Wood changes its size when its moisture content changes. The size change is different along each of the planes of wood growth - radial at right), tangential (T) and lengthwise (X). So, it's important that woodworkers know when the moisture content of their wood has reached equilibrium with the workshop, so that its dimensions have settled down.

What is the moisture content (MC) of wood compared to its dry weight? Typically 60% for green hardwoods, up to double that for softwoods. The moisture is in two forms - chemically bound and free. The first aim of seasoning lumber is to degrade the chemical bonds to water, so that all that remains is free to move. This happens faster at higher temperatures, which is why kiln drying saves so much time. However, too-high kiln temperatures degrade wood, and most kiln drying is done as quickly as possible to produce cheap construction grade softwood. That's why kiln drying has a bad name among instrument makers.

Skilled kiln drying can actually produce better wood than air drying. When wood is air dried, the outside dries faster than the inside, and this results in residual stresses in the wood. If the kiln humidity is controlled to match that of the wood throughout the process, and the high temperature is used just to speed up the rate at which the chemical bonds are degraded and moisture equilibrium is reached, residual stresses can be significantly reduced below those of air dried wood. But, there is no way to know, just looking at a piece of wood.

[Dano]

It looks to me like there is a fine line between seasoned and degraded. My thoughts on the subject, it's kinda like a fine wine, aged/seasoned. I ain't no judge of fine wine and I dang sure haven't seen the benefit of seasoned wood, outside of the fact folks think they can charge more, for storage I guess. 

[DCM4]

I haven't noticed a difference as a bowyer.  And I'm not sure we are as concerned with lumber maintaining it's dimensional shape as furniture makers and such.  But it would be hard to argue wood doesn't change over time.  Anybody who has fooled with decades old furniture or timbers could testify.  I've seen oak boards you have to drill first to put a nail in.  If you think about that "bound" moisture, and heat breaking those chemical bonds in the text Gordon quotes, I imagine those resins and such could behave differently if allowed to reduce and form over a longer period.  Kinda like the grain structure of carbon steel, annealed versus hardened.

[Gordon]

I suspose many bowyers may not be concerned with the demensional shape of the wood. But if you work with reaction wood (such as vine maple), that is an important consideration. The other benefit of drying, of course, is that wood is strongest, i.e. resistent to bending, when it is dry. The "bound" water that the author refers to is the water that is physically bound within the walls of the wood cells as opposed to the "free" water that exists in the cell cavities. Once this water is removed, I can see no particular benefit to letting the wood sit around and further "season".