Identify Tree by Leaf: Leaf Shape Chart and 5-Step Key

To identify a tree by its leaf, answer five questions in a fixed order: is it a needle, a scale or a broad flat leaf; are the leaves opposite or alternate on the twig; is each leaf simple or compound; what does the edge look like; and what is the overall shape. Each answer removes most of the remaining candidates, so by the time you reach shape you are usually choosing between a handful of trees rather than hundreds.

• Leaf type - the Ohio key published by OPLIN opens with exactly this choice: needle-like leaves single or in bundles of 2 to 5, scale-like leaves, or broad flat leaves.
• Arrangement - the Georgia 4-H forestry judging slides define alternate as one leaf per node, opposite as two per node and whorled as more than two. Virginia Tech's dendrology primer adds that most species are alternate.
• Simple or compound - a simple leaf has one blade joined by its stalk to the woody twig; a compound leaf is divided all the way to a non-woody midrib (rachis) into leaflets.
• Margin - smooth, finely toothed, coarsely toothed or lobed.
• Shape - the outline of the blade, plus the shape of the tip and the base.

Check several healthy leaves from the same tree before you commit, because one chewed or shaded leaf can mislead you.

Virginia Tech's dendrology primer names each common outline with a tree that shows it well. Use it as a chart: find the outline, then check the example tree.

• Lanceolate (long and slender) - black willow
• Spatulate (narrow base, very broad tip) - water oak
• Cordate (heart-shaped) - eastern redbud; see our heart-shaped leaf page for the other seven candidates
• Orbicular (round in outline) - silver maple and most other maples
• Ovate (egg-shaped, broadest near the base) - zelkova
• Elliptical (symmetrical ellipse) - spicebush
• Obovate (egg-shaped, broadest near the tip) - the leaflets of buckeye
• Oblong (elongated oval) - Chinese chestnut
• Deltoid (triangular) - eastern cottonwood, whose leaves are 3 to 6 inches long on a flattened stalk (Virginia Tech fact sheet)

Conifers have their own chart. Virginia Tech lists scales on the cedars such as northern white-cedar, single needles on spruces, firs and hemlocks, and needles in bundles (fascicles) on pines - two per bundle in Table Mountain pine, three in loblolly pine. Counting needles per bundle is the fastest way to split the pines.

The margin is the next most useful feature after arrangement. Virginia Tech's primer gives four types with a named example for each:

• Entire (smooth edge) - blackgum
• Serrate (small saw-like teeth) - red maple
• Dentate (large teeth) - American chestnut
• Lobed - white oak; the lobes stick out and the sinuses cut in

Lobed leaves carry one more split that matters. In oaks, a bristle at the tip of each lobe means the red oak group and a rounded lobe means the white oak group - our oak leaf page walks through it. In maples, the number and depth of the lobes and the shape of the sinuses separate sugar, red, silver and Norway maple, covered on our maple leaf page.

Beginners often mistake one compound leaf for a twig carrying many small leaves. The Georgia 4-H slides give the test: an axillary bud sits in the angle between a whole leaf and the stem. Trace the stalk back until you find that bud; everything beyond it is one leaf.

The same slides then sort compound leaves by how the leaflets are arranged:

• Pinnately compound - leaflets along one undivided axis, with an odd or even number of leaflets (examples in the slides: ash, walnut, sumac)
• Twice pinnate (bipinnate) - the axis itself branches, and each branch carries leaflets
• Palmate - leaflets spread from one point like fingers, as in buckeye

Combine this with arrangement and the field shrinks fast. Opposite plus compound points to ash or buckeye, both on the opposite-leaved MAD Cap Horse list; compound leaves that are not opposite belong to other groups, such as the walnuts and sumacs in the Georgia slides.

These are the leaves people most often photograph in eastern North America, each with the feature that names it. Measurements come from the Virginia Tech dendrology fact sheets unless noted.

• White oak - 4 to 7 in., 7 to 10 rounded lobes, no bristles (white oak wood)
• Northern red oak - 5 to 8 in., 7 to 11 bristle-tipped lobes (red oak wood)
• Red maple - opposite, finely serrate edge (soft maple wood)
• Silver maple - opposite, round (orbicular) outline
• Eastern redbud - alternate, heart-shaped, 3 to 5 in., smooth edge, thin and papery
• American basswood - alternate, 5 to 6 in., serrate, heart-shaped base with one side lower than the other (basswood)
• Eastern cottonwood - alternate, triangular, 3 to 6 in., flattened leaf stalk (cottonwood)
• Black walnut - compound, Virginia Tech's example of a compound leaf (black walnut)
• Black willow - long, slender lanceolate leaves
• Northern catalpa - whorled in threes or opposite, heart-shaped, 5 to 12 in., smooth edge
• Blackgum - smooth (entire) edge

If your leaf is one of these, the linked wood pages tell you what the timber from the same tree looks like.

A phone can do most of the work if the photo is good. There are three kinds of tools, and they work differently.

• Photo search - Google Search Help describes Google Lens in the Google app: tap Lens in the search bar or pick a photo from your camera roll, point at the object and tap Search, and select a smaller area of the image for more specific results. Google uses a plant photo as its own example.
• Question keys - the Arbor Day Foundation offers an illustrated, step-by-step key that starts by choosing your region, plus a tree guide covering more than 200 trees and shrubs. OPLIN's What Tree Is It? covers Ohio and lets you key by leaf, by fruit or by name. These ask you the questions above instead of reading a photo.
• Identification apps - WoodLens reads a photo of a leaf, bark or wood grain and returns the most likely species with a confidence level, and shows alternative candidates when two trees look alike. The guides on this site are free.

Whichever you use, photograph one whole leaf flat against a plain background, include the stalk and the point where it joins the twig, add a second shot of the underside and a third of the twig showing how the leaves are arranged. A single close-up of a leaf surface is the photo that most often fails.

Some trees change leaf shape from branch to branch. Virginia Tech notes that red mulberry leaves may have no lobes or be deeply cut into lobes on the same tree, and that royal paulownia leaves on young trees often show coarse teeth or even lobes.

When the leaf evidence is split, move to the next feature rather than forcing a match: bark on a mature trunk (see identify tree by bark), fruit, buds and twigs. In winter, buds keep the same arrangement as the leaves, because Virginia Tech's primer points out that buds grow where the leaf meets the twig, so an opposite-leaved tree still shows opposite buds after leaf fall.

Leaf identification images work best when they are grouped by what you can see, not by plant family. The Footsteps in the Forest photo gallery of eastern US trees, which shows roughly 50 species, is organised into nine visual groups:

• needle-like or scaly leaves
• compound leaves
• leaves with no teeth, spines or lobes
• toothed or spiny edges
• lobed leaves
• triangular or heart-shaped leaves
• trees with different leaf shapes on the same tree
• exceptionally large leaves
• oddly shaped leaves

Two tips from the gallery are worth borrowing for any picture key. First, find the bud: a leaf starts at the twig, so on a compound leaf the individual leaflets are not leaves, and mistaking one for the other sends you to the wrong group. Second, if a leaf could fit two groups, look in both rather than debating which one is correct. The gallery's authors also say plainly that leaves alone rarely give a positive species identification, which is why the key above adds bark, fruit and buds.

TreeIdentifier's leaf tool gives the same advice we give for WoodLens: lay a single leaf on a plain background, photograph it from directly above in good light, and fill most of the frame, because leaf shape, margin and venation are the strongest features for the software. When one leaf is ambiguous, add photos of the bark and the whole tree.

Three additions make the difference between a guess and an answer:

• The underside. Hairs, tufts in the vein corners and rusty midrib hairs live there; see our black cherry leaf and oak leaf pages for examples.
• The twig. A shot of how leaves attach shows opposite, alternate or whorled arrangement, which splits trees faster than shape.
• More than one leaf. Take leaves from low shade and from high sun; the oak page explains why they can look like different species.

WoodLens reads leaf, bark and wood-grain photos.