Appearance of Hickory Tree Leaves
Hickory trees have distinctive leaves that set them apart from other trees. Examining the size, shape, color, texture, and other features of hickory leaves provides helpful identification cues to recognize these iconic trees.
Hickory leaves tend to be large, compound leaves with pointed leaflets that turn golden yellow in autumn. Understanding the visual profile of hickory foliage aids tree identification and highlights the natural beauty of hickories.
Hickory Leaf Shape and Structure
Hickory leaves are pinnately compound, composed of leaflets arranged along a central rachis or stem. There are typically 5-9 oblong, pointed leaflets per leaf.
The leaflets have toothed edges and grow in an alternate pattern along hickory branches. Each leaflet connects to the rachis via its own individual petiole or mini-stem called a petiolule.
The terminal leaflet at the end of the rachis is usually the largest. Hickory leaflets exhibit an elongated oval shape that tapers to a tip. Their outline is broadest near the middle or base of the leaflet.
Oblong with Pointed Tips
Hickory leaflets have a characteristic oblong, lance-head profile with a narrowed base and sharp point at the apex. This tapered silhouette helps distinguish them from the leaves of other trees.
Toothed Edges
The margins of hickory leaflets feature rounded teeth or serrations. These "nibbled edges" offer an easy identification cue compared to trees with smooth leaf edges.
Compound Leaves
Unlike simple leaves with a single blade, hickories bear compound leaves divided into multiple leaflets. Having 5-9 leaflets per leaf is consistent across hickory species.
Alternate Arrangement on Branches
Hickory leaves connect singly to branches in an alternate pattern. This means leaves emerge at different heights rather than directly across from each other.
Size and Dimensions
In addition to their signature shape, hickory leaves are quite large compared to many other trees. Understanding the range of sizes helps gauge height when identifying hickories.
Length Ranges from 4 to 12 Inches
Mature hickory leaves stretch between 4-12 inches long from the base of the leaf stem to the tip of the terminal leaflet. Young or stunted leaves may fall short of that. But any substantially smaller leaves generally indicate a different tree species.
Width of 2 to 6 Inches
The width of the entire hickory leaf structure spans approximately 2-6 inches. Leaflet widths range between 0.8-2.5 inches for individual components.
New Leaves Have Red Tint
When first emerging in spring, the new leaves and leaflets of hickories often exhibit a reddish or bronze cast. This fades gradually to green as leaves mature and expand.
Number of Leaflets
Hickory leaves contain an odd number of leaflets nearly always totaling 5, 7, or 9 leaflets per leaf. This consistent trait aids identification.
Typically 5 to 9 Leaflets
Having either 5, 7, or 9 leaflets contributes to the classic hickory leaf look. Other compound leaves may have less or more leaflets.
Terminal Leaflet Present
Hickory leaves feature a terminal leaflet larger than the others. This end leaflet helps distinguish hickories from trees where all leaflets are approximately the same size.
Leaflets 3 to 6 Inches Long
The individual oval leaflets comprising each hickory leaf range from 3-6 inches in length. Their leathery texture allows the leaflets to achieve this sizable proportions without being delicate.
Leaf Surface and Texture
Hickory leaves offer visual contrasts between top and bottom sides. The upper surface presents as smooth and shiny, while the underside seems pale, dull, and mildly hairy in texture.
Glossy Upper Surface
The top face of hickory leaflets has a noticeably glossy, varnished look. Light reflects brightly off the slick upper surface compared to other tree leaves with more matte finishes.
Paler and Hairy Underside
The bottom side of hickory leaves features a paler hue and slight hairiness. Tiny hairs along the veins make the underside feel smooth rather than slick.
Smooth Texture
Despite variances between upper and lower surfaces, hickory leaves maintain a uniform smoothness overall. Their leathery skin resists wrinkling or curling unlike thinner leaves.
Leaf Color
Hickory leaves transition through an array of shades during their annual cycle. Understanding typical hickory leaf colors aids identification amidst seasonal changes.
Green Upper Surface in Summer
During spring and summer when hickory trees are actively growing, the leaf upper surface presents a medium to dark green color. Shades vary slightly among the different hickory species.
Golden Yellow Fall Foliage
As autumn approaches, the green chlorophyll in hickory leaves starts breaking down, allowing vivid yellow and golden orange pigments to shine through before the leaves drop.
Dark Green Color in Spring
Hickory leaves emerge with a reddish tint in early spring, but this quickly transforms to a lush, dark green hue within a couple weeks after leaf out.
Venation Patterns
The vein structure within hickory leaves follows distinctive layouts and designs. Becoming familiar with hickory leaf venation assists with ID'ing leaf specimens correctly.
Pinnate Venation
Hickory leaves contain pinnate venation where the veins or "ribs" flow parallel to one another in a feather-like pattern toward the tip of the leaflet.
Prominent Main Vein
A prominent midrib vein runs centrally through each leaflet, extending from the base out toward the point. Hickories lack palmate venation where veins radiate from a common point.
Veins can have Hairy Tufts
On the lower leaflet surface, small hairy tufts sometimes emerge where secondary veins intersect. These "joints" offer an extra ID marker when examining hickory leaves up close.
Extra Floral Features
Beyond the leaves themselves, hickories produce additional photosynthetic structures that contribute to energy production and growth.
Petiole Connects Leaf to Branch
The petiole or leaf stem connects hickory leaves to twigs and conveys water and nutrients. This short green stalk acts like a pipeline between branch and leaf.
Stipule Leaf-Like Structures
Early spring growth includes stipules which are small green leafy outgrowths flanking leaf buds as they form and unfold. These soon drop away as leaves mature.
Bud at Leaf Base
A sharp-tipped leaf bud nestles in the axil where petioles join hickory twigs. This helps generate next year's leaves and extends the branch system.
Scent
Crushing or scratching hickory leaves releases aromatic oils with a distinctive citrusy perfume. Detecting this scent offers supplemental evidence when identifying hickories.
Strong Aromatic Odor
The compounds within hickory leaves give them a potent odor noticeably stronger than most other tree leaves if abraded or mashed.