Wood turing black after milling

[Cool Hound Luke]

I've noticed for some reason my pine lumber is turning to a black color during air drying. What causes this? I noticed a few months ago I cut some pine and they dried with no black color, so I'm wondering if it might be the Alabama humidity. What do yall think?

[Tom]

Yes, it is the humidity, or the rain....

If the mold is black, it's probably mildew and you surely don't want that on/in your lumber.  Mildew stays put and comes back alive after airdrying to smell up a house or barn and kill the wood.   You need to unstack that wood, kill the mildew and restack it in a dry place.   I've used a 3:1 water to household bleach solution, sprayed on each board with a garden sprayer(to kill it) and then pressure washed the board to get the mold off.

If you have ever dealt with mildew in a bathroom, you will know what a problem it can be.

[wwsjr]

I assume that if you are air drying you have at least 1" stickers in your stacks. I have had lot of problems this year due to the wet and humid weather here in MS. I sawed pine for board and batten on the inside of our firehouse. It had been on sticks for about 30 days, lots of black mildew. We used a 50/50 mix of bleach/water that cleaned completely. I have also had to use pressure washer to clean before sealing. I have tried using the bleach mix as I stack, spray each layer of boards with pump sprayer, place dry sticks, then place the next row. This takes time but seems to work. I am not sure if I have broken any EPA laws or not, I want my lumber to stay bright.

I never flat stack lumber unless it is at customers location and he is pulling off, loading on trailer, etc to move. I usually cut stickers from edging and provide to customer. Not dry, but better than nothing.

If the logs are brought to my location, my sawing price includes stickering lumber, banding with poly as I pull off mill. I have much better satisfied customers by doing this each time. 

[Cool Hound Luke]

Yeah, I'm using 1 x 1's to stack my boards and I do have them stacked in a open shed, so no rain is getting on them. I thought is might be the humidity which is very high here right now. I didn't know it was mildew. Thanks for your help. I will try the bleach trick and pressure washer.

[ljmathias]

I just had to do the same thing with white mold on a bunch of 38" wide pecan boards we sawed out at 4/4- cleaned 'em up real nice.   Now that the humidity is down, they should be fine... :D :D :D

Lj

[terrifictimbersllc]

a bunch of 38" wide pecan boards we sawed out at 4/4-  :D :D :D

Lj

How did you saw out 38" wide 4/4 boards?

[WDH]

With pine, you might put a fan blowing thru the stack to keep the air moving.  You cannot do that with some hardwoods like oak because the wood might dry too fast and check/honeycomb.  That is usually not a problem with pine.

My experience is that poor air flow is the culprit.  On those heavy, humid days with no wind or breeze, the water vapor from the drying boards does not escape, raising the humidity around the boards.  That higher humidity with the heat is a breeding ground for mold, mildew, and fungus.

[bandmiller2]

I realize everyone doesn't have this option but we avoid cutting pine when the weather is warm and humid,do it in the winter.As stated a fan blowing on well stuck pine will give you a chance.This is where a kiln comes in handy. Frank C.

[ljmathias]

I misspoke some- log was 38" wide when I started and we carved it down so the saw just cleared and then flat sawed to the bunks.  Forgot to measure the final width so it's whatever an LT40 throat allows; amazingly, no checking yet.  And talk about hard and dense!  The boards are around 10' long and weigh a ton... took two of us to man-handle them into the stickered stack.  Oh, I cut them at 5/4 for the treads- should be plenty stiff for stairs.  In hindsight, I'd cut them 4/4- I always build stairs with 2X tread and risers underneath anyway so I can use them while building the upstairs plus it eliminates all the squeaks and talking when you use them.  I glue the treads and risers on and finish with cut nails- real pretty rustic look- can you say "overbuilt?"  We'll probably just glue the pecan on though, as my son and DIL are going for a less rustic look than I like to do...

Lj

[Cool Hound Luke]

I will try to spray any new pine that I cut with a bleach mix while stacking as wwsjr mentioned while the humidity is still high. Is it just pine that turns black with high humidity? I have some cedar, red oak, and yellow poplar that I want to cut, but I sure don't want them to turn black. If they will turn black, I will wait until this fall to cut them. What do yall think?

[WDH]

I have had yellow poplar turn black, but not oak or cedar.

[Chuck White]

I sawed some White Pine about 1½ months ago and stacked & stickered in my "open" garage.

A couple of days ago, I was out looking it over and there were only 3 boards (1x6's) that were moldy and black.

I thought it was odd that there were only 3 out of around 40-50 boards that were affected.

The 3 boards that got moldy were the very top boards on the pile