Air Drying and Blue Stain in Southern Pine

Advice on stacking and drying SYP rough lumber prior to kiln-drying it and making mouldings out of it. May 13, 2013

Question
I have a steam dry kiln that will dry around 20,000bf per charge. It is currently set up for hardwoods. Drying SYP from very green will overwhelm it. The boiler can't keep up with the low wet bulb required to dry it and my vents do not recover heat.

So, I have a SYP molding order that will require 15 to 18K bf of SYP. I normally buy 5/4 KD 1x6 decking locally and redry it on down to 10 to 11% MC. Problem is, I will have to glue up any molding that is over 5.5", as that is what the decking is.

But there is a sawmill that is cutting some SYP for ties and he is selling the off fall. It has widths up to 12". I was thinking about buying a couple of truckloads of this green SYP, putting it on sticks until I need it, letting it air dry, then popping it in the kiln and drying on down to 10%.

My only concern is blue stain. Will SYP easily blue stain air drying while on sticks? Will I be able to see any blue stain in the log as soon as it is cut, while putting on sticks?

Forum Responses
From Professor Gene Wengert, forum technical advisor:
Hardwood kilns can dry SYP if you load the kiln about half full.

Blue stain is an issue with SYP, but not as bad as other pines. Log stain is indeed easy to see. The main thing for air drying is to get the wood in a fast drying location and protect it from direct rainfall, if possible. Compared to most hardwoods, pine is a piece of cake, but does require some urgency in handling.


From the original questioner:
So, you think if I put it on sticks right away, put a lid on it, keep the stacks fairly open, it should be okay? Like hardwoods, the first few days are the most critical, right?

From Professor Gene Wengert, forum technical advisor:
If you have good air flow and if the weather is okay, you will be fine. Note that right under the bark is the riskiest. The first days are indeed the most critical.

From contributor W:
Most blue staining happens in the log before the lumber is even cut. The key is to have fresh cut logs that have not had the opportunity to blue stain. In the South, blue stain can happen in a week when it is hottest and humid.
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