Does Rougher Wood Dry Faster?

Surface conditions do not control the overall rate of drying. July 28, 2008

Will a given thickness of wood dry faster with a rough texture than the same thickness with a smooth finish?

Forum Responses
(Sawing and Drying Forum)
From contributor F:
I have recently read that some sawmills plane their freshly sawn wood, as it will dry with less degrade (warp, etc.) and will also dry faster. It’s a bit thinner, thus leaving higher quality dried wood.

From contributor B:
Yes, because there is more surface area to volume a rough surface texture, all other things equal, will result in faster drying. And yes, pre-surfaced lumber dries faster because it is thinner, and with better quality because the uniform thickness means more uniform force applied from stickers. Pre-surfacing can also help reduce depth and severity of surface checks.

From Gene Wengert, forum technical advisor:
If your question is addressing the fact that roughness means more turbulence of the air and therefore more moisture removal and better heat transfer, from a technical point of view, this is true. However, the surface or boundary layer of the air does not control drying rates except when the wood is fairly wet.

Drying is controlled most of the time by the movement rate of moisture within the wood, so slight surface or boundary layer differences do not affect things from a practical point of view. (As mentioned, if you have a rough piece and then plane it, making it thinner, drying will change, but not because the surface is smoother).

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