California black oak (Quer- cus kelloggii) is in the red oak group of species, but its source of supply (
growing primarily in northern California
and southwest Oregon), physical properties (weaker than most red oaks, but
machines better), appearance (not as
red, but 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, common-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. The
wood makes excellent lumber that is
well suited for furniture, cabinets, and
flooring. Because there is not a well
developed market, buyers must contact
potential sawmills personally. Then try
a few sample pieces of lumber that can
be tested. ;
California black oak
Underutilized wood has high density, fine grain.
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by Gene Wengert
firstname.lastname@example.org WOOD EXPLORER
Density. The green specific gravity (SG)
is 0.61; at 6 percent MC, the SG is 0.67.
The weight, when dried to 6 percent
MC, is 39 pounds per cubic foot or 3. 3
pounds per board foot.
Drying. The wood dries slowly and
with a high risk of checking and honeycomb. Staining from fungi is common.
Shrinkage in drying of 9. 7 percent is
lower than for eastern red oaks.
Gluing and Machining. This wood
The world’s source
for in-line moisture
machines well, but does require sharp
tools and proper machine set-up to avoid
chip-out. Avoid drying tunder 5. 5 percent
MC. This wood, as with all higher density
species, glues with considerable difficulty.
Stability. It takes a 4 percent MC
change for a 1 percent size change tangentially and 7 percent change radially.
Strength. For dry wood, the ultimate
strength (MOR) is 13,000 psi and hardness is 1100 pounds.
Color and Grain. Heartwood is tan
with a reddish hue, but it is not as red as
many other red oaks. Because of slow
growth, grain is finer than other red oaks
and can show lots of character). Grain is
coarse, often with pin knots.