Safe Time for Tight Stacking

How long can you safely "dead stack" wood without air spaces before stickering the pile? February 27, 2013

My question is how long can you stack "wet off the saw" wood in a tight stack (waiting to go into the kiln) before staining and molds will occur? The wood will be western maple,oak and Doug fir. If coordination goes correctly the tree(s) will be cut down one day and hauled to the mill to be sawed and then stacked on the trailer and off to the kiln on the first part of the third day. I havenít noticed a problem with the Doug fir after being tightly stacked for 24-48 hours. Iím just wondering about the maple and oak and how long it can be pushed in a tight stack?

Forum Responses
(Sawing and Drying Forum)
From contributor K:
Some lumber we can let sit around for weeks dead stacked, like walnut, cherry, and oak. Maple I worry about but your few days sounds okay. The big factor is the outside temp and humidity. If itís 110 degrees with 100% RH it might get moldy pretty quick. Up north in the winter when itís frozen it might stay fine for months.

From Gene Wengert, forum technical advisor:
As a rule of thumb, at 50 F, we say that fungal staining is quite slow, but at 70 F, much faster and at 90 F about the fastest, and by 110 F, things have slowed down. At 90 F, you might see stain within 24 hours. D-F has a low initial MC typically, so staining is not really active. However, maple, especially because it is white and so any staining at all is noticeable, and oak to some degree, both have a higher risk of staining than D-F.

With the white woods, there is also enzymatic staining, which can be grey and look a lot like fin gal staining. In warm weather, 24 hours is a risky storage time. The bottom line is that 24-48 hours is not too long in many cases, but in a few situations, it can be too much.

From the original questioner:
I will use this information as a guideline and fine tune from here, subject to change depending on the weather as I live in Oregon. Heat is not a problem most of the time. I will use low 70ís F and a 24 hour max stack time on maple as a guide to keep the staining out of my wood. This is one of the reasons I am doing it this way, to produce a bright, clean, and beautiful product and to try and minimize the handling aspect. As I will be coordinating will the kiln operator I should be able to stay with in the 18-28 hour range but will plan on stickering if I anticipate longer times.

From Gene Wengert, forum technical advisor:
Hopefully your kiln operator knows that for maple you need an 8 or 10 F depression initially (actual kiln conditions and not just what you set for the controls).