Tree identification is always a matter of detective work, and especially so in winter, when the leaves are not present to offer their distinctive clues.
It takes time to learn to recognize the patterns of bark and buds, but the learning process is great fun, and once learned, winter tree ID is a satisfying skill to have mastered. It is also useful for those who want to select trees for firewood or construction, tap trees for sap, or practice primitive skills that require particular species for tool-making.
This article applies only to deciduous, leaf-bearing trees. For information on needle-bearing trees, see Pines, Conifers, Evergreens.
The first step in identifying a leafless tree is to determine whether the tree has an opposite or alternate growth pattern. If the tree is short enough, look at the twigs and notice whether the buds occur in pairs on opposite sides of the twig. If the twigs are out of reach, look up into the canopy and see if there are paired twigs. If there are some, then the tree is opposite. (Note that one of the pair often breaks off.) If there are none, it is alternate.
There are few deciduous trees with opposite twigs, buds, and leaves. It does not take long to be able to distinguish the lacy, meandering twig pattern of maples from the strongly upward thrust of the stout twigs of ash trees. Here are a few other distinguishing characteristics:
White ash: Thick twigs, only slightly curved, not much branching of twigs. Bark furrows are deep, ridges tend to form diamond patterns. Buds are dry and scratchy.
Sugar maple: Slender, much-branching twigs. Bumpy bark, not flaky, usually with whitish-grey lichen coating part of the surface. Buds sharply pointed, with many layered scales.
Red maple: Slender, much-branching twigs. Bark smooth to flaky. Reddish buds.
Norway maple: Twig thickness intermediate between ash and sugar maple. Bark resembles white ash. End buds long and smooth, magenta in color.
Dogwood: Small tree, often shrubby. Flowering dogwood, an ornamental that sometimes appears in open woods, has onion-shaped buds. (Note that there are many shrubs with opposite twigs, but they are beyond the scope of this article.)
Catalpa: Some branches opposite, some in whorls of three. Thick twigs. Very long, cylindrical seed pods.
Alternate Trees with Lingering Fruit or Pods
Some species are easily identified by the seed pods or fruits that stay on the trees through most of the winter.
Alder: Usually shrubby, forming thickets alongside water. Bears tiny, woody, conelike fruits.
Birch: Bears tiny, conelike fruits. See Birch Trees in Winter.
Black Locust: Thick, flat seed pods. Twigs have small paired thorns.
Honey Locust: Long, twisting flat seed pods. Thorns over one inch long protrude from the dark bark.
Staghorn sumac: Spires of red, fuzzy berries. Usually grows as a tall shrub. Bark is covered with tan fuzz. (Smooth sumac has hairless twigs and less fuzzy red berries. Poison sumac has hairless twigs and white berries.)
Sweetgum: Round, prickly seed pods.
Sycamore: Seeds are closely packed in balls that hang from twigs. Bark variegated in green, white, tan patches.
Tulip-tree: Tan, cuplike seed containers, one to two inches long, remain on the twigs. Bark ridges make diamond shapes, similar to white ash.
Witch hazel: Stringy yellow flowers appear in fall and may persist into winter. They are followed by clusters of irregularly roundish seed capsules. The trees are small and often shrubby (with multiple, slender trunks).