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Trees of Yosemite (1932, 1948) by Mary Curry Tresidder

Oak Family

Fagaceae

The oak family is divided into two main groups which may easily be distinguished by the coloring of the bark: White Oaks and Black Oaks. In general the White Oaks produce their acorns in one season and the Black Oaks in two, but it happens that our local White Oak, the Canyon Live Oak, is an exception to this rule, and both our oaks therefore take two seasons for ripening their acorns.

Two oak trees are commonly found in the Yosemite Valley proper and elsewhere in the Park through the Transition Zone. One is a White Oak, the Maul or Canyon Live Oak; it belongs to the live oaks. The other, which is deciduous, is the California Black Oak or Kellogg Oak. There is a third oak, commonly a shrub, which with manzanita and chinquapin covers the dry, sunny slopes at the rim of the Yosemite Valley and in similar places throughout the Park. This is the Huckleberry Oak, Quercus vaccinifolia Engelm., which is quite similar to the Canyon Live Oak, except that its thin acorn-cups lack the golden fuzz and its leaves are more often entire than toothed. It is sometimes classified as a subspecies of the other, but since it is a shrub rather than a tree this brief mention must suffice. Another oak is often seen through the foothills, with the Digger Pine, but it seems not to reach the Park; this is the Blue Oak, Q. douglasii H. & A., a deciduous species, one of the White Oaks; it is readily distinguished by the bluish-green color of its foliage.

The leaves of the oaks have a great variety of sizes and shapes in the different species, but in all they grow singly on the branch. The trees themselves usually have a sturdy bole sending off a number of powerful branches into a wide crown of rather dense foliage. Oaks sprout freely around the cut-off stump; they have a long, strong tap-root, insuring their vitality.

The staminate flowers of the oaks hang down in a loose catkin from the lower part of the young shoot, while the pistillate flowers, which develop into acorns, are borne above on the new twig. As the acorn requires two seasons to mature, by the time it is ripe the new growth has pushed beyond it.

Squirrels, blue jays, and woodpeckers vie for the acorns in laying away their winter stores. The oaks were the orchards of the Indians, for whom acorns were the staff of life; after leaching them to remove the bitter element, they pounded them to a flour in their mortar rocks, and then cooked them as a gruel or made them into loaves in their cooking baskets, heating the water by means of hot stones. The mortar rocks are usually found under or near a group of oaks; they often have several dozen holes of varying depths worn in one rock.

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