851 Quercus rubraCommon Names: northern red oak Family: Fagaceae (beech Family)
The northern red oak is a dramatic and powerful tree that normally grows 60-80 ft (18.3-24.4 m) in height with a trunk diameter of 2-3 ft (0.6-0.9 m). In the richest sites of the Ohio River Valley, some specimens get 150 ft (45.7 m) tall and have trunk diameters in excess of 5 ft (1.5 m). Northern red oaks that grow in the open have short stout trunks that split into several large branches 15-20 ft (4.6-6.1 m) above the ground, and broad, symmetrical crowns. Those that grow in the forest tend to have longer, unbranched boles and narrower, rounded crowns. The bark is dark brown, nearly black, and broken into ridges and furrows. All oaks have simple, alternate leaves; those of the northern red oak are 5-9 in (1.5-2.7 cm) long and have 7, 9 or 11 unequal lobes; each lobe usually has three pointed teeth with little bristles on the tips. The leaves turn red or orange in the fall and usually persist on the trees until early winter. All oaks have both male and female flowers on the same trees. The male flowers are slender pendulous catkins, conspicuous in early spring, and the female flowers are inconspicuous little spikes. As the leaves are unfolding, spring winds blow pollen from the red oak's long yellowish staminate catkins onto the tiny greenish pistillate flowers.
Great oaks from little acorns grow, and northern red oak's acorns take two years to mature. They are oblong, about 1 in (2.5 cm) in length and a little less in width. The bitter nuts are seated in flat shallow cups which are covered with tiny scales. Many other species of oaks are similar to northern red oak, and several species are known to hybridize with it. It isn't always possible to identify oaks to species with complete certainty. Distinguishing characteristics of northern red oak include 1) an acorn cup that is flat, like a saucer, and encloses only the lower one-quarter to one-third of the nut; 2) leaves that are thin and papery, not glossy, hairless beneath and with sinuses between the lobes extending about one-half way to the midvein; and 3) winter buds on twig tips hairless and not angled. Black oak (Q. velutina) is very similar but it has winter buds on twig tips that are gray furry and sharply angled, and acorn cups that are more like a cup, enclosing about half the nut. Southern red oak (Q. falcata) has hairy winter buds and smaller acorns that are only 0.5 in (1.3 cm) long with cups extending about a third of the way up the nut. Pin oak(Q. palustris ) has leaves with very deep sinuses between the lobes, extending fully two-thirds of the way to the midvein, and acorns only 0.5 in (1.3 cm) long. Scarlet oak (Q. coccinea) has deep acorn cups, enclosing a third to a half of the nut. Shumard oak (Q. shumardii) has tufts of hairs in the junctions of the veins on the underside of the leaves, deeper sinuses between the lobes, and acorn cups that enclose abut a third of the nut.
A handful of northern red oak cultivars have been named. 'Aurea' has new leaves of golden yellow. 'Schrefeldii' has very deeply divided leaves with the lobes often overlapping each other. 'Splendens' has bright red fall color.
The northern red oak, Quercus rubra, ranges from Nova Scotia and Maine, west through southern Ontario and Minnesota, and south through Iowa and eastern Oklahoma, to Alabama and northern Georgia. It is replaced by the southern red oak (Q. falcata) in eastern Texas and the southeastern Coastal Plain. Northern red oak occurs in mixed forests at low to moderate elevations. It sometimes is a dominant species in the forest, but usually northern red oak grows in association with other trees of the eastern mixed forest such as white oak (Quercus alba ), American elm (Ulmus americana), white pine (Pinus strobus ), hickories (Carya ovata), sugar maple (Acer saccharum), white ash (Fraxinus americana), sweetgum (Liquidambar styraciflua), and tulip tree (Liriodendron tulipifera).
CultureNorthern red oak is perhaps the fastest growing of all the oaks; it can put on more than 2 ft (0.6 m) per year in its youth, and begin producing acorns in as little as 20 years. Northern red oak does best in a light, sandy loam that is neutral to slightly acidic. It can tolerate heavier soils, but suffers in calcareous soils. Light: Saplings can tolerate some shade, but the tree will need full sun to reach its potential. Moisture: Red oak has water needs typical of most large trees. It grows best with regular watering but established specimens are quite tolerant of normal droughts. Hardiness: USDA Zones 4 - 8. Northern red oak may be problematic in zone 8. Better to use southern red oak in the south. Propagation: Fresh acorns take 2-3 months to germinate. Northern red oaks tend to produce abundant acorn crops every 2-5 years. Most acorns are eaten by insects and other animals before they have a chance to germinate. Northern red oak is easy to transplant successfully.
Northern red oak is an excellent choice for homeowners who want a quality shade tree as quickly as possible. These stately trees are often planted on golf courses, parks, and campuses. Northern red oak is tolerant of urban air pollution and widely planted as a street tree in the American Northeast and Midwest. It is tolerant of salt spray and does well even in exposed coastal positions. Northern red oak is highly esteemed for its autumn foliage, and its symmetrical habit produces a handsome winter silhouette. The northern red oak is the most important of the red oaks for timber production.
There are more than 500 species of Quercus occurring in North, Central and South America, Europe, Asia and northern Africa. They occur in temperate and subtropical zones and in the tropics at high elevations. Mexico has over 150 species of oaks, and the U.S. boasts about 60 species. Most oaks are trees, but many are shrubs, and some are little more than sprawling ground covers. The oaks can be divided into two main groups: Members of the red oak group have leaves that are entire, toothed or have pointed lobes with bristles on their tips, and bitter acorns which take two years to mature. Members of the white oak group have leaves that are entire, toothed or have rounded lobes, but without bristles on their tips, and their acorns, which are not bitter, mature in just one season.
As a group, the oaks are just about the most important trees in the forests of eastern North America. The wood of most species is valuable for construction and fuel. The acorns are extremely important wildlife food, and are the primary overwintering food for a great many species of birds and mammals. Most oaks are beautiful landscape specimens and favored by homeowners for shade trees. Many of the oaks contribute to the autumn foliage display with their rich browns, reds and russets.
Steve Christman 11/11/00; updated 10/17/03, 7/12/07