California black oak is in the red oak group of species, but its source of supply (It grows primarily in northern California and southwest Oregon.), physical properties (It is weaker than most red oaks, but machines better), appearance (It is not as red, but has tighter grain.), and processing differences (Drying is difficult.) merit a special discussion of this species.

The tree reaches maturity in 90 years or longer. At that age it is 50 to 100 feet high and 14 to 40 inches in diameter; the larger sizes are when the tree is growing on good sites. On poor sites, the tree is quite scrubby in appearance. The acorns were widely used as a food by Native Americans, often being dried and ground into flour. Unfortunately, many of the California black oak trees have died in recent years due to a fungal disease, commonly called “Sudden Oak Death.”

This species of red oak, also called Kellogg oak and western red oak, and in its growth area is called black oak, is tremendously underutilized. I believe that much of the reason for this underutilization is that too many people tried to use softwood drying equipment and techniques to dry this very refractory (which means prone to surface checking and cracking) wood. (California black oak is much more likely to check in drying than northern and Appalachian red oaks.) The drying results were disastrous. However, with proper “Southern red oak” drying procedures and conditions, this oak can be dried without much defect development.

Another reason for underutilization is the scarcity of NHLA trained graders in the area; the NHLA grading scheme is one of the marketing keys for any hardwood.

Finally, the typical mill supply of logs produces 38 percent No. 1 Common and Better lumber; this is marginally low and will require good markets for the lower grades in order for the sawmill to be profitable. In fact, some mills have developed proprietary grades for so-called “low grade” material. In reality, low grade is a valuable raw material for many manufacturers. Oregon State’s Wood Innovation Center can often provide technical assistance with processing this species.

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