Hickory trees are a common sight across North America, recognized for their strong wood and edible nuts. This guide will help you recognize these deciduous trees by examining their overall appearance, bark, leaves, and the unique features of their nuts and fruits.
Overall Stature and Form
Hickory trees typically present a robust and upright form, often reaching impressive heights. Many species, like the shagbark hickory, can grow between 60 to 90 feet tall, with some even exceeding 100 feet. Their canopy shape varies, often appearing broad and rounded or oblong.
The main branches usually grow in a spreading or ascending manner, contributing to its generally symmetrical crown. Young trees may exhibit a more narrow or even spindly appearance, particularly when growing in competition within a forest. Over time, they develop a more substantial and defined structure.
Identifying Bark Characteristics
The bark of a hickory tree is one of its most defining features, varying significantly among species and with age. Many hickories, such as the shagbark and shellbark varieties, are famous for their “shaggy” appearance, peeling away from the trunk in long, thick, curling strips or plates.
Other species exhibit different bark patterns. For example, pignut hickory bark can be gray with deep, interlacing ridges that may appear somewhat scaly but generally do not flake as dramatically as shagbark. Mockernut bark often has deep, narrow furrows with interconnected ridges that tend to smooth with age, though some mature trees may also show peeling. Bitternut bark, in contrast, is typically light grayish-brown and remains relatively smooth, rarely flaking deeply.
Leaf and Branch Details
Hickory leaves are compound, meaning each leaf consists of several smaller leaflets along a central stem (rachis). They are typically “odd pinnately compound,” with an odd number of leaflets and a single leaflet at the tip. Leaflet count ranges from 5 to 17, depending on the species; for example, shagbark hickories commonly have 5 to 7, while pecan hickories can have 9 to 17.
Individual leaflets are usually lance-shaped to obovate, with serrated edges, and vary from 2 to 8 inches long. The terminal leaflet at the end of the rachis is often larger than the others. During spring and summer, the leaves are typically medium to dark green, transitioning to vibrant golden yellow in the fall. Twigs of hickory trees are generally stout, and terminal buds are often large and broadly ovoid, useful for identification, especially in winter.
Nuts and Fruits for Identification
Hickory nuts and their husks are definitive identifiers for hickory trees. Nuts are encased in a woody outer husk that starts green and hardens to a dark or light brown as it matures. This husk typically splits into four sections when ripe, usually between September and December, revealing the hard-shelled nut inside. Husk splitting varies; some species, like pignut hickory, may only partially split or require manual removal.
Nuts come in various shapes—circular, heart-shaped, or oblong—and can be slightly flat or rounded. Shell texture ranges from smooth with minimal veining to considerably irregular and furrowed. Shell thickness also varies by species. Shellbark hickories produce some of the largest nuts with thick shells, while sand hickories have smaller nuts with thinner shells. The presence of these characteristic nuts, often found on the ground in autumn, provides strong evidence for identifying a hickory tree.