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.

Green Ash
Photo credit: David Cappaert, Michigan State University, Bugwood.org

 

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

 


 

Ash branches are characterized by oppositely arranged
buds and leaves on the twigs. Twigs tend to be stout, able
to hold large compound leaves.
Image Credit: Rebecca Hargrave, Cornell Cooperative
Extension

Opposite Branching:

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.

 


 

White Ash leaf, note small leftlets (9 total, 4 paired and one terminal)
and the brown bud at leaf base.
Photo credit: Rebecca Hargrave, Cornell Cooperative Extension

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 branches are characterized by oppositely arranged buds and leaves
on the twigs. Twigs tend to be stout, able to hold large compound leaves.
Image Credit: Rebecca Hargrave, Cornell Cooperative Extension

Samara:

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.

 


 

The diamond pattern bark is distinctive in green
and white ash trees.
Photo credit: Keith Kanoti, Maine Forest Service,
Bugwood.org
Black ash trees have flakey bark as they age. But,
a diamond pattern may still be seen.
Photo credit: Keith Kanoti, Maine Forest Service,
Bugwood.org

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).

 


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