How to identify a dead tree's species

Bark patterns that last after death

Bark is where most dead trees are named. A few patterns are distinctive enough to work alone:

• White ash: ashy gray to brown, with interlacing corky ridges forming obvious diamonds, according to the Virginia Tech white ash fact sheet; older trees may be scaly. The same sheet describes the leaf scars as round at the bottom and notched at the top, with a bud sitting in the notch, a detail you can still see on dead twigs.
• Hackberry: smooth and gray-brown when young, soon breaking into corky individual warts that later run together into rough, irregular ridges, per the Virginia Tech hackberry fact sheet. Its twigs are slender and zigzag.
• Shagbark hickory: develops its shaggy plates as it matures, UNH Extension notes. The long plates curving away from the trunk survive well on a dead tree.
• Red oak: UNH notes that its fissures often show red coloring.
• Black gum: mature trees have very deep fissures, per UNH.

When bark starts to slough off, look at the pieces on the ground as well as the trunk: the outer surface of a fallen slab still shows the pattern, and its thickness and color add a clue.

Ash and elm: the trees most often found dead

In eastern and midwestern towns, two groups of trees account for a large share of the dead trees people ask about, because each has been hit by an introduced pest or disease.

Ash. USDA APHIS says the emerald ash borer has caused the death and decline of tens of millions of ash trees in North America since it was first found in southeast Michigan in 2002, with infestations detected in 38 states and the District of Columbia (as of the page read on 2026-10-21). A dead ash is named by its opposite branching, diamond-ridged bark and notched leaf scars. APHIS lists the beetle's signs: D-shaped exit holes in the bark, S-shaped tunnels under it, vertical bark cracks, bark stripped by woodpeckers looking for larvae, dead branches near the top and excessive branching on the trunk. Those marks point to ash borer, which attacks ash, so they also support the species call. The ash page covers the living tree.

Elm. The USDA Forest Service's silvics manual for American elm describes its characteristic vaselike crown, and notes that open-grown trees usually fork near the ground into wide arching crowns. It also says that scores of dead elms in forests, shelterbelts and towns are testimony to Dutch elm disease. The Morton Arboretum's Dutch elm disease page says highly susceptible elms may die in the year of infection, rates American elm as extremely susceptible, and rates lacebark and Siberian elm as highly resistant. Brown streaks under the bark of affected branches are further evidence, but only a laboratory test confirms the disease.

So a dead tree with a tall vase shape, alternate branching and ring-porous wood in a town that once had elm-lined streets is very likely an American elm.

Crown shape and branching from a distance

Before walking up to a dead tree, step back and look at the whole silhouette against the sky. Opposite branching often shows from the ground as paired limbs. The vase shape of American elm, the narrow oblong crown and straight trunk that Virginia Tech describes for white ash in good sites, and the zigzag twigs of hackberry are all visible without touching the tree. Compare the dead tree with living ones nearby, too: a dead tree in a row or a woodlot is often the same species as its neighbors. The winter tree identification guide has a twig key for 12 common eastern trees that works just as well on a dead tree with its twigs intact.

When only the wood is left

An old snag with no bark and no twigs still has wood, and the cut end of a fallen branch or a fresh cut on the trunk carries most of the information. Michigan State University's extension bulletin Identifying Wood: A Guide and a Key recommends a 10x hand lens and a sharp pocket knife, and explains what to check:

• Pores. Hardwoods have pores; conifers do not. In ring-porous woods, such as oak, elm, ash and hickory, the pores at the start of each growth ring are much larger than the rest. In diffuse-porous woods, such as maple and cottonwood, they are about the same size through the ring.
• Rays. The lines running from the center toward the bark are broad and distinct in oaks and beech.
• Heartwood color and smell. Only heartwood, the darker center, has a characteristic color and odor; the bulletin notes that no other American wood has the color of eastern redcedar, and that odor helps with Douglas-fir, basswood and the cedars, sometimes only after a fresh cut is moistened.
• Resin canals. Pines show tiny resin openings scattered along the growth ring, often visible to the eye.

Weathered gray wood shows none of this until you cut below the surface. If the tree has already been cut down, the tree stump guide walks through reading a stump, including the sprouts many hardwoods send up after cutting. If you plan to burn the wood, the firewood guide compares heat values by species.

Confirm the tree is really dead

Name the species first, then be careful about calling the tree dead. Many healthy trees look dead from November to April. Texas A&M Forest Service staff forester Gretchen Riley, quoted by Texas A&M AgriLife, uses a plain rule: a tree is dead if it has had no green leaves for a full growing season. The same article says dead or dying trees in natural areas are not usually dangerous, but those near homes, roads and power lines can be hazardous when they have structural defects, and that a doubtful tree should be evaluated by a certified arborist. Knowing the species helps that conversation: it tells the arborist whether ash borer or elm disease is likely, and which nearby trees of the same kind are at risk.

Where a photo app helps

Tree Identifier, an iPhone app that uses a cloud AI model and needs an internet connection, identifies trees from one photo, and a photo of the bark or of a dead leaf from the ground is often enough for it to suggest a species with its key traits. Ask the follow-up chat under the result what else to check, such as the bud arrangement. If you allow location, the Tree Map pins the tree so you can find it again in spring and compare it with living neighbors. Check the name yourself against the bark, buds and wood described above. Tree Identifier cannot tell you whether a dead tree is safe, what killed it, or whether it will fall; those calls belong to a certified arborist.