Red Oak

Quercus rubra

twig, acorn, and leafThe red oak is one of the largest and most important timber trees. One of the fastest growing of the oaks, it attains a to 80 feet and a diameter of two to three feet. It has a wide, spreading head with few far reaching branches. Found growing over southeastern Canada and the northeastern United States, it reaches west to central Minnesota, eastern Nebraska and Kansas. It is found over most of Iowa on a variety of soils, except on the drier clay uplands. It prefers moist, rich soils on north, east or northeast exposures.

acorn and barkThe tree has a single, lobed leaf with seven to eleven pointed or bristly-tipped lobes. The lobe sinuses reach one-half way to mid-vein. The leaves are thin, firm, dull green above, yellow-green below, varying considerably.

The fruit is a large, broad, rounded acorn with a very shallow disk-like or saucer-shaped cup or cap.

The twigs are small, slender, greenish brown to dark brown. On young branches the bark is smooth and gray to greenish. On the trunk it breaks into long, narrow, shallow ridges flat and smooth on top. The underbark is light red.


  • Have seven to 11 toothed lobes that are separated by sinuses extending about halfway to the midrib.
  • Contain tannin, a substance that makes the leaves leathery and hinders decomposition.
  • Dark red, fading to brown but may remain on the tree well into the fall.
leaves, twig, and bark
Branching: alternate

Bark: reddish brown when young; mature tree is dark, furrowed and often laced with broad shiny strips (ski trails).

Height: 70 to 90 ft.

Trunk Diameter: 2 to 4 ft.

Longevity: 300+ yrs.

Tolerance: intermediate

Range: eastern U.S. except for the south Atlantic and Gulf Coastal Plains

Fun Facts: Acorns provide a food source for numerous birds and animals: Ruffed grouse, nuthatch, blue jay, wild turkey, red, gray and fox squirrels, bears, deer, raccoons.

Question: How many root beer barrels could you make from a red oak tree?
Answer: None - red oak has big pores, so all the root beer would leak out.


Identify Another Tree

This key was developed by "bt" in June 1982. It was put into HTML format by Stephen Ostermiller in July 1997. Copies of the entire guide in zip format that may be taken to camp on a laptop are available to those who write.