Identifying mold/rot in roughcut hemlock and how to treat it

[bogart_bogesley]

I'm not sure if this is the right sub-forum to ask this in but I'm trying to identify what appears to be mold/rot that has formed on the window jambs in my house that's still under construction.  I've been surfing around on google images but I've yet to find something that looks quite like it.  I don't exactly remember at what point this formed as I recently fell victim to an illness that really screwed up my memory (among other things) and a lot stuff is still fuzzy.  These brown patches may have always been there for all I know.

I was hoping someone here might be able to help me identify what kind of mold/rot this is and possibly how I might go about treating it.  It would be unfortunate if I need to completely remove this wood but I'll do what's necessary.  While the structure is wrapped in plastic, it's open to the outside air around the perimeter just below the roof overhang on all sides.  I've attached several pictures below.

 

 

 

[Don P]

That looks like extractives bleeding out to the surface where water/damp has run or pooled, especially happens on lower edges and undersides like in that bottom pic. @GeneWengert-WoodDoc over on the drying forum can probably confirm and suggest remedies. I'd try sanding and then maybe oxalic acid myself.

Check out surface brown stains pg 5 here;
https://fpinnovations.ca/media/publications/Documents/wood-discoloration.pdf

[bogart_bogesley]

Thanks a lot Don.  I'll send Gene a PM.  I sure hope it's just something cosmetic

[GeneWengert-WoodDoc]

When moisture moves through wood, it sometimes carries water-soluble chemicals along.  At the surface, the water evaporates, but the chemicals are left behind.  Similar to evaporation of salt water from a dish, the salt is left behind.  These chemicals can darken with exposure.  Sometimes this is called brown stain or coffee stain.  It likely involves an enzyme, which means that the wood was not heated to over 130F in drying.  It is also called an oxidation, enzymatic reaction.  Oxalic might lessen the color.

[bogart_bogesley]

When moisture moves through wood, it sometimes carries water-soluble chemicals along.  At the surface, the water evaporates, but the chemicals are left behind.  Similar to evaporation of salt water from a dish, the salt is left behind.  These chemicals can darken with exposure.  Sometimes this is called brown stain or coffee stain.  It likely involves an enzyme, which means that the wood was not heated to over 130F in drying.  It is also called an oxidation, enzymatic reaction.  Oxalic might lessen the color.

Thanks Gene, and yes this wood has gotten wet on several occasions.  If this is just something cosmetic I'm not really worried about it.  But nonetheless I'll keep an eye on it and compare old and new pictures to see if it's spreading.

[mitchstockdale]

I have noticed this discoloration on a lot of wood and plywood in the house I am building.  It was exposed to many rain storms last summer and fall and where water found a path between headers, floor joist and plywood it looks almost identical.  

Since I am just getting around to finishing the inside now I find myself checking the spots to see if they are wet... but they are bone dry .