Ash trees have opposite, pinnately compound leaves. Few other trees combine those two features.
Identifying ash
Scientific name: Fraxinus
How to recognise it
- Opposite leaves, each divided into leaflets along a central stalk, usually with one at the tip.
- Most species have between five and eleven leaflets.
- Seeds hang in bunches, each with a single narrow wing.
- Bark is often ridged, in a diamond pattern on older white ash.
Species
- White ash (Fraxinus americana): leaflets paler beneath, bark with diamond ridges.
- Green ash (F. pennsylvanica): leaflets green on both sides, very widespread.
- Black ash (F. nigra): stalkless leaflets, grows in swamps.
- European ash (F. excelsior): black buds in winter, widely planted and native in Britain.
Look-alikes
Boxelder (a maple) also has opposite compound leaves but usually has fewer leaflets and paired winged seeds. Hickory, walnut and sumac have compound leaves too, but they are alternate.
Threats
The emerald ash borer, an insect from Asia, has killed very large numbers of ash trees in North America. If you find ash trees with thinning crowns and small D-shaped holes in the bark, report it to your local forestry service. In Europe, a fungus called ash dieback is causing widespread loss.
Uses
Ash wood is strong and flexible and has been used for tool handles, baseball bats and oars.