White Oak (Quercus alba)
The white oak is the classic eastern oak species. It is tall (eighty to one hundred feet) and stout (three to four feet diameter) with heavy, nearly horizontal branches that form a rugged, widely spreading crown in open habitats. Under shaded forest conditions the trunk is tall and straight and runs up into a tight, small crown.
The size, longevity, and durability of this and other oak species account for
the designation of most of the hardwood forests of central and southern North
America as "oak forests".
Leaves and Bark
The leaves of the white oak are five to nine inches long and two to four inches wide. They have five to nine blunt-ended lobes and vary in exact size and shape in different layers of the canopy. The leaves are relatively heavy and thick and may remain attached to the tree through the winter. Fallen leaves accumulate in dense, slowly decomposing masses on the forest floor. The white oak's bark is light gray and divided by shallow fissures into small, vertically aligned blocks.
The roots of the white oak are prodigious. At the end of the first growing season, for example, a three inch white oak seedling will have a one-half inch diameter tap root that extends over a foot down into the soil. These roots grow faster than the above ground tree and solidly anchor the white oak. There is within the red pine area of the Nature Trail a large, dead white oak that has for many years continued to stand firmly in place, well supported both by its very strong trunk wood and its extensive and still intact root system.
The white oak flowers in the mid-spring with the unfolding of its leaves. An individual tree produces both male flowers ("catkins") and female flowers. The catkins represent an important spring food source for gray squirrels and many other animals. Fruit from the fertilized female flowers are the familiar acorns that on the white oak mature after a single season. These acorns (which are produced in abundance only every four to ten years) are readily eaten by many species of birds and mammals. The gray squirrel is particularly fond of white oak acorns and is very important in both their dispersal and their planting.
Growth and Longevity
While the white oak grows extremely slowly, individuals can live for five hundred to six hundred years (especially in deep, moist but well drained soils). Through their slow and steady growth and remarkable longevity, white oaks can come to dominate all of the other tree species within a great variety of forest ecosystems.