What causes the red stain?

[Mark Webb]

We got the hickory sawn on Saturday afternoon late and left it stacked till the morning and the boards we hadn't cleaned the saw dust off had gotten a red stain on them. What caused this?
Mark

[Tom]

probably oxidation of the chemical in the wood.  Lots of woods will do that.  It's a good idea to get rid of the sawdust as soon as you can because it produces "Shadow Stain", a similar thing to what you experienced and is, symptomatically, variable coloring in the surface of the wood.   Sawdust, having such a large, relative surface area is quick to react to the elements and easily contaminated by pathogens.