Green Ash

Fraxinus pennsylvanica

Green_Ash_Fraxinus_pennsylvanica.jpg

Illustration of green ash leaf.
Green ash, Fraxinus pennsylvanica
Paul Nelson
Family

Oleaceae (olives)

Description

Green ash is a medium to large tree with a straight, tall trunk, high branches, and a rounded crown.

Leaves are opposite, compound, 8–12 inches long, with 7–9 lance-shaped leaflets, 4–6 inches long, finely toothed; upper surface dark green, dull, smooth; lower surface paler green, more or less hairy; leaflet stalks (at least the lower ones) narrowly winged. Leaves turn bright yellow in autumn.

Bark is brown, shallowly grooved, with narrow, flat-topped, interlacing ridges that form diamond or X-shape patterns.

Twigs are stout, rigid, gray, smooth.

Flowers April–May, male and female on separate trees; both male and female flowers in clusters, small, green, lacking petals.

Fruits August–September, in dense clusters to 8 inches long; fruit 1–2 inches long, a flattened, smooth, somewhat oarlike, winged seed, with the wing partially around the seed.

Size

Height: to 90 feet; spread: 40 feet

Habitat and conservation

In the wild, green ash grows along streambanks and in moist bottomlands. In cultivation, it prefers wet soils and full sun but is adaptable to a wide range of conditions. Widely planted. Sadly, this is one of the trees most vulnerable to the emerald ash borer, a tremendously destructive invasive exotic beetle that has already killed perhaps 100 million ash trees in the United States and nearby sections of Canada. This insect will probably eventually kill nearly all the ash trees on the continent.

image of Green Ash Distribution Map
Distribution in Missouri

Statewide.

Status

Common. In the future, however, this and all ash trees may become uncommon or extirpated. The emerald ash borer kills virtually all the ash trees wherever it goes. It has already gained a toehold in Missouri, is solidly present in Ohio, Michigan, northern Indiana, and eastern Illinois, and it is expanding its range. So far, no one has found a way to stop its spread.

Human connections

Widely planted as a shade tree in cities and at homes, and for erosion control, windbreaks, and land reclamation. Ash wood is hard, strong, and able to absorb blows without breaking, and it is used for many products, including boat oars, tennis racquets, and guitars.

Ecosystem connections

The seeds, which female green ash trees produce in abundance, are eaten by songbirds, quail, turkey, wood ducks, and small mammals. The boughs provide perches and nest sites for birds and squirrels. The shade they collectively produce creates a forest habitat, which many species require.