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Northern Red Oak vs Black Oak

Although these species sometimes look blatantly different, significant variation in individual leaf shape and other characteristics can make these species challenging to tell apart in some cases. There is some overlap in habitat, with black oak preferring slightly drier sites and northern red oak being more shade-tolerant. The two species can also hybridize and form intergrades, so it may not be possible to identify all individuals.

Northern Red Oak (Quercus rubra)

Black Oak (Quercus velutina)

A large tree and one of the major components of the forests of eastern North America, the northern red oak has a wider range than its name may suggest, extending quite far into the "deep south", but also covering a large portion of the northeastern U.S. and into Canada.
A large oak with a wide distribution across eastern North America, common in much of its range, often a canopy tree in forests. More tolerant of dry, nutrient-poor conditions than most large oaks.
Leaves typically have 7-11 lobes.
Photo © Aaron Boers, CC BY 4.0.
Leaves typically have 5-9 lobes.
Photo © Even Dankowicz, CC BY 4.0.
Bark of mature trees often has longer, unbroken vertical strips of smooth bark. Cracks between bark are shallow and can be broad, often showing a slight reddish color on close inspection.
Photo © Katja Schulz, CC BY 4.0.
Bark more rugged and fragmented overall. More horizontal cracks and smaller unbroken pieces of bark. Deeper and narrower cracks between outer pieces of bark. Outermost pieces of bark rougher.
Photo © Even Dankowicz, CC BY 4.0.
Mature buds are slightly smaller, and either lack hair entirely, or are only pubescent at the tip. More rounded and less likely to have sharp angles in cross-section.
Photo © Leila Dasher, CC BY 4.0.
Mature buds are slightly larger, and are covered in dense whitish hair. Buds look more angular in cross-section.
Photo © Shirley Zundell, CC BY 4.0.
Larger acorns; cap encloses less (1/3rd to 1/4th) of the acorn.
Photo © Rob Norris, Public Domain.
Smaller acorns; cap encloses half or nearly half the acorn.
Photo © Shirley Zundell, CC BY 4.0.
Leaves of seedlings in shade often more oval-shaped, with widest point closer to the middle of the leaf, and a taper towards the tip. Glabrous (lacking hairs) except possibly a few tufts of hair in vein axils on underside. Not usually shiny, and sometimes slightly glaucous (waxy bluish-white.)
Photo © Claire Secrist, Public Domain.
Leaves of seedlings in shade often dramatically wider towards the tip, relatively flat-across at the tip, and narrow at the base. Leaves can be finely pubescent or shiny, but not glaucous. Often have a more wrinkly texture.
Photo © Donna, Public Domain.

References & External Resources

These short lists show only links helpful for ID. For a complete list of references and resources also covering other aspects of ecology, visit the links section of the full article on each plant, which is the first entry here.

Northern Red Oak (Quercus rubra)

Black Oak (Quercus velutina)

Quercus rubra | Go Botany (About This Site)

Quercus velutina | Go Botany (About This Site)

Quercus rubra (Northern Red Oak) | Illinois Wildflowers (About This Site)

Quercus velutina (Black Oak) | Illinois Wildflowers (About This Site)

Northern Red Oak | Virginia Tech Dendrology Factsheets (About This Site)

Black Oak | Virginia Tech Dendrology Factsheets (About This Site)

Quercus rubra | Flora of North America (About This Site)

Quercus velutina | Flora of North America (About This Site)

Quercus rubra | Biota of North America Project (BONAP) (About This Site)

Quercus velutina | Biota of North America Project (BONAP) (About This Site)