White oak (Quercus alba) and black oak (Quercus nigra) both grow in a wide variety of habitats and soils. Both are tall and long-lived, with some trees lasting more than 400 years and reaching heights topping 100 feet. Black and white oak are both deciduous and lose their leaves in winter, spreading thousands of acorns for squirrels to eat and people to trip on. Each tree has markedly different characteristics, though. Learn what they are, and soon you'll be able to tell the difference at a glance.
Leaf Shape and Color
White oak has a narrow, 5- to 6-inch leaf with softly rounded, deeply cut lobes. Leaf color is a medium green on top, with a gray-green underside. Fall foliage for white oak is reddish brown. Black oak leaves are about the same size, but the lobes are sharply pointed and serrated. Leaf texture is also leathery and is a deep green. The fall foliage of black oak is dried-blood red. Both oaks can sometimes hold onto their leaves until late winter.
White oak acorns are bright green, about an inch long, with a medium-brown, textured cap that covers the top third of the nut. Black oak acorns are slightly smaller and rounder, and their caps are bigger and reach farther down the nut surface.
Twigs and Buds
Twigs and buds on white oak are soft and flexible, hardening off during the growing season. Twigs are bright, greenish yellow, while buds are tiny and reddish. Black oak twigs and buds are only slightly different, with the twigs being green, with larger, pinkish buds at their crotches.
Bark and Growth Habit
White oak has shaggy bark that grows more textured with age, making for a very rough surface on older trees. Black oak has much smoother bark, though there is still some texture. Both bark colors are a medium, silvery gray. Though surroundings and climate can affect the shape and growth habit of both oaks, white oak tends to be a slimmer shape, while black oak sprawls easily and has a very wide spread at maturity.