Ash (Fraxinus spp.) Identification
Fraxinus spp. Characteristics
Hosts Ash trees (Fraxinus spp.) are the only known North American hosts of EAB. Ashes have pinnately compound leaves arranged opposite one another on the branch. Each leaf bears 5-9 leaflets. The fruit is a winged seed (samara). Some ash species have bark with interlacing ridges that form a diamond-like pattern when mature.
Identification of Emerald Ash Borer
Once-Compound Leaf | Oppositely Arranged |
Fruit/Seed (samara) | Bark of White Ash |
Some Non-hosts of the EAB That Could Be Confused with Ash
- Box-elder (Acer negundo) has pinnately compound leaves with opposite arrangement, but only 3-5 leaflets per leaf that are somewhat more coarsely toothed.
- Hickories (Carya spp.) and walnuts (Juglans spp.) have pinnately compound leaves with alternate arrangement.
- Buckeye (Aesculus spp.) leaves are arranged oppositely, but are palmately compound (leaflets radiate from a single point).
- Maple (Acer spp.) and dogwood (Cornus spp.) leaves are oppositely arranged but are simple rather than compound.
Resources
Michigan State University Extension Bulletin "
Distinguishing Ash from other Common Trees
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633.9 kB
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." (4 pp, .pdf)
