Home and Woodlot Owners
ASH TREE IDENTIFICATION
Ash trees are generally easy to identify. All three varieties of ash trees - white, green, and black - possess distinct characteristics.
Steps in Identifying Ash Trees:
Consider these quick points when identifying ash trees:
- Opposite Branching (with stout twigs)
- Pinnate Compound Leaves
- 5-11 Leaflets
- Single Samara
- Pronounced Diamond Pattern Bark
Buds, and therefore leaves and branches, grow directly across from each other. Only a few trees in New York State have opposite branching, including Ash, Maple, and Horsechestnut/Buckeye.
Pinnate Compound Leaves:
Compound leaves are leaves made up of multiple leaflets. Pinnate leaflets are arranged linearly along a rachis, or stem. White ash generally has 5-9 leaflets. Green ash has 7-9 leaflets. Black ash has 7-11 leaflets. You will find a bud at the base of each leaf where it meets the stem.
Ash fruit is a single samara, or seed surrounded by dry, oar-shaped wings that help with dispersal. The wing on the green ash fruit, seen here, extends down almost to the base of the seed, whereas the wing on white ash fruit only extends to the top half of the seed. Both are about the same size, 1 -2 inches in length.
Diamond Pattern Bark:
As white and green ash trees age their bark develops distinct diamond patterns. Young green and white ash trees have smooth bark. Black ash trees start with warty or smooth bark and grow to have flakey bark as they age, but, a diamond pattern may still be seen. An easy differentiation between green and white ash; the upper branches of white ash tend to be smooth to the top, even in older trees, whereas the upper branches of green ash tend to be rough all the way up.
Look Alike Trees:
Although ash trees are quite unique looking, there are a few trees that could be mistaken for ash.
- Norway Maple: These trees also have opposite branches and diamond-pattern bark, but they have large, simple leaves and paired samaras (fruit).
- Box Elder: Sometimes known as the Ash-leaf Maple, this tree also has opposite branching, compound and pinnate leaves, and diamond-pattern bark. However, the box elder has three-five lobed terminal leaflets, and reddish stems and young bark.
- Elderberry: Elderberry has opposite branching and pinnate, compound leaves. Important differences from the ash tree is that elderberry is a shrub, with soft, pithy twigs, and berries.
- Mountain-ash: This tree is not a true ash. Like the ash, it has pinnate, compound leaves. Unlike the ash, the mountain-ash has smooth bark, alternate branches, and berries.
- Hickory and Walnut: This group of trees, including Shagbark Hickory, Bitternut Hickory and Black Walnut, primarily has pinnately compound leaves, but alternate branching, nuts, and varying bark types (some of which can look diamond like).
- Ash Tree Identification Fact Sheet: Hit sheet for Ash Tree Identification, Cornell University.
- Emerald Ash Borer: Ash Tree Identification This presentation developed by Cornell University contains information and photographs to identify ash trees and common look-alike trees.
- Know Your Trees, Cornell University education bulletin, 2001.
- Cornell Woody Plants Database, Cornell University tree identification searchable online tool.
- Dendrology at Virginia Tech, Virginia Tech tree identification searchable online tool