Streaks in red oak
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Q: In our last shipment of red oak, we noted that about 25 percent of the lumber had thin, long grayish streaks wandering throughout the boards. The supplier says that this is normal, but we cannot use this discolored wood in our chairs and tables. What is this and what can we do? One person told us that this is typical of black oak. We are small enough that we do not have a lot of clout with our supplier.

A: First, any supplier that does not work with his customers, big or small, needs to "take a hike."  Please look for a new supplier that has your interests in mind.

There are two types of dark streaks that can appear in oak lumber. One type is quite dark, often associated with small sections of white or bleached looking wood. The black streaks look like someone took a black marker pen and doodled all over the board, inside and out. This is white rot decay and is certainly a grading defect. However, your description of the marks makes me think that you have the second type of streaking.

Light black streaks are common in the butt log of trees grown in wet or swampy conditions. Did you notice that there were wider than normal growth rings or that the rings were wavy? (I do not think that it is restricted or associated with black oak in particular.)

The streaks are not a defect in the NHLA grading rules as they are classed as mineral. However, it certainly is an appearance defect in exposed furniture, cabinets, etc. For the future, you need to add a line in your specification about the streaks being unacceptable, with such lumber being returned for full credit. (Note that the NHLA encourages using the rules as a starting point for developing your customized needs. You are not being weird if you have special requirements.)

I am not sure, but does it sound like maybe someone has already gone through the red oak that your supplier has and pulled out the good stuff? Perhaps you are getting the fallout? (Note: It would not be legitimate to sort lumber into different categories within a grade and then sell you the lower grade stuff, unless you were told about it. So, if you have the fallout, it is not in keeping in the spirit, and perhaps the legality, of the NHLA rules.)

At this point, you have to negotiate carefully with your supplier, as he probably has the legal rights on his side regarding the admissibility of this mineral streak (unless he has "creamed" the grade and you are getting the fallout). I would think that any resistance on his part to work with you is certainly not good customer relations for future orders.

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Gene Wengert

Gene Wengert, “The Wood Doctor” has been training people in efficient use of wood for 45 years. He is extension specialist emeritus at the University of Wisconsin-Madison.