Flood Plains Prairie Forest Species
Urban Forest Species
Windbreak Forest Species

Green Ash
(Fraxinus pennsylvanica)


Fraxinus is the ancient Latin name for "ash." Pennsylvanica is the Latinized name of Pennsylvania. When European botanists
were first naming North American trees, they gave some names in reference to where the specimen was collected. Other
common names for green ash include red ash, swamp ash, and water ash. The Lakota know green ash as pséhtin can, the
Omaha as tashnanga-hi , the Winnebago as rak and the Pawnee as kiditake .

 Green ash belongs to the Oleaceae, the olive family, along with lilac (Syringa vulgaris ). Its leaves are deciduous , opposite, pinnately compound with 7 to 9 leaflets . Leaflets are 3 to 4 inches (8 to 10 cm) long, ovate and have a smooth margin. Ash flowers are separated into male and female flowers, both are very small and appear in the spring before the leaves. Fruits are 1 to 2 inches (2.54 to 5 cm) long, narrow samara. Twigs are slender, gray to greenish brown, with a pointed bud at the tip. The bark is ashy-gray, divided into shallow furrows shaped into diamond patterns.

Green ash is native to the central and eastern regions of the United States. It is found from Maine to eastern Montana and
Minnesota to central Texas and northern Florida. Green ash is native to South Dakota, naturally occurring only along rivers
and streams, and in wooded draws. It is also planted throughout the state.

Native Distribution
Green ash grows on the bottomland soils found along rivers. It will tolerate an occasional flooding, perhaps once or twice a
year, but can not survive in areas that have a permanent high water table. Green ash grows well on heavy clay, bottomland

Green ash is intolerant to moderately tolerant of shade competition. It generally comes into a forest after cottonwoods.
However, on clay soils it is often a pioneer species. Green ash seeds mature in the fall. They usually are wind-dispersed
within a few hundred feet of the parent tree. Some are carried far distances by water. Once green ash begins to develop,
American elm begins to grow in their shade and will eventually crowd out the ash. This pattern is now beginning to change.
Due to Dutch Elm disease, green ash is becoming the climax species. There are many areas along the Big Sioux River where
the flood plain forests consist of a few large cottonwoods, several dying elms and hundreds of green ash.

Natural History

Green ash is a very tough tree. It is very drought tolerant because of its extensive root system. Trees 40 feet (12 m) tall have
been found to have roots that grow outward more than 50 feet (15 m) and go down as deep as 3 or 4 feet (91 to 122 cm).

Life Span: Green ash has an average life span of 100 to 120 years.

Size: The largest green ash is in Cass County, Michigan. This tree is 242 inches (615 cm) in circumference, 131 feet (40 m)
tall and has a branch spread of 121 feet (37 m). The largest green ash in South Dakota is in Sioux Falls. It is 157 inches (399
cm) in circumference, 80 feet (24 m) tall and has a crown spread of 57 feet (17 m).


While found naturally in moist flood plains, green ash adapts well to dry soils. Because of its drought tolerance and rapid
growth, green ash is extensively used as a windbreak tree. Many improved green ash cultivars , such as Summit and Patmore,
are planted as shade trees.

While green ash is firm, it is not as straight-grained as white ash (Fraxinus americana ), so it is not an important timber
species. The American Indians used green ash for bows, with the young stems made into arrow shafts. Green ash is also an
important symbol and is used as part of the Sacred Pole of the Omaha Indians.

Publication of the Green Ash fact sheet was funded by the S.D. Department of Agriculture, Division of Forestry, Pierre, SD.