Douglas fir turning black

[Al Miles]

Just before Christmas i custom cut some Douglas Fire on a client's property. I told him to have his helpers clean all the sawdust off the timbers and sticker them under cover as they came off the mill. That didn't happen and they have been getting rained and snowed on for a month. He is now cleaning and stacking the wood but the sawdust and some of the surface of the wood is turning dark colour already.
Is there a method to get the stain off the fir? I've heard spraying the wood with a bleach-water solution will remove the blackened stain. Anyone know if that will work?
Thank you for any suggestions.

[btulloh]

It works to some degree.  Easy and cheap.  Won't make it look like new.  Deck cleaner will do a good job if they need to look fresh sawed again.

[Chop Shop]

Most times it will just go away as the wood dries and gets some air flow.

Tell him NOT to tarp it.   Just a cover on top like plywood or tin roofing.

Once the moisture goes away it will stop.   If it stays wet it will just go away later when theres no sugar left to feed the mold.

[GeneWengert-WoodDoc]

At this point, you are likely dealing with mold or other fungi that are just on the surface.  The key for control is to remove the moisture they need for active growth.  So aggressive dryingis needed to prevent future growth.  Because it is likely just surface now, you should be able to plane or sand it off fairly well.  Bleach will affect the wood's color too.  Any chance you could surface a piece, or even just scrape it with a knife, to make sure it has not gone into the wood?  If it is deeper, then we have a different fungi.

[Brad_bb]

If you use the bleach solution, you do not need any more than 5% bleach mixed with water.  Tests have showed that any greater than 5% provides no additional benefit and does not kill the fungi/mold faster. 

[Ljohnsaw]

If you use the bleach solution, you do not need any more than 5% bleach mixed with water.  Tests have showed that any greater than 5% provides no additional benefit and does not kill the fungi/mold faster.

Brad,
Are you are talking about 5% of bottled bleach in solution?  Not that it would be a huge difference, but what strength of bleach?  The cheap stuff is 3% HCL, normal is is 5 or 6% and pool grade is 10% HCL.

[GeneWengert-WoodDoc]

Note that bleach will kill existing fungi, but if the conditions favorable for fungi growth- -moisture, oxygen, temperature and food- - remain, then new fungal activity can occur, both on the surface and deeper.  In fact, bleach is in water so the increased moisture content can encourage new growth.  Therefore, you do need to dry the wood aggressively to make future fungal growth impossible.