Identifying characteristics:
The white ash is the most common, most planted native ash in the US.
Trees generally grow to 70 or 80 feet tall with a long, straight trunk
and an open, rounded crown. Leaves
are opposite, pinnately compound and 8 to 12 inches long. The 5 to 9 leaflets
(usually 7) are 2 to 6 inches long, with smooth margins or with infrequent,
rounded teeth. Leaves are dark green above, sometimes glossy, and paler
and usually hairless below. Fall color is early and varies from yellow to
bronze-purple. Male and female flowers
are apetalous and occur in clusters on separate trees. Flowers appear with
or before the leaves in April or May. The fruit
is a paddle-shaped samara produced in dense, 7- to 9-inch-long clusters.
Each seed is flattened and winged, the wing 1 to 2.5 inches long and not
extending along the seed cavity. The small leaf scars are nearly
round, with a V-shaped notch in the top. Bundle scars are numerous
and form a fine, curved line. The small, rounded buds are inset in
the leaf scars, and have dark brown, overlapping, hairy scales. The upper
pair of lateral buds are situated against the terminal bud, with no space
between. Bark is gray, thick and deeply
fissured with narrow, interlacing ridges around diamond-shaped areas.
Similar species:
Ecology:
Distribution: The white ash is an eastern species, hardy from zone
3 to 9, occurring from Nova Scotia to Minnesota, south to northern Florida
and eastern Texas. In Iowa it is found west to the Cedar River in northern
Iowa, to the Des Moines River and its tributaries in central Iowa, and to
the Missouri River in southern Iowa.
Habitat: This species grows primarily on upland slopes and ridges in Iowa, seldom on bottomlands where green ash predominates. Only the seedlings are tolerant of shade, and are usually abundant in forests. Grown trees are intermediately shade tolerant and are seldom a dominant forest species. They are pH adaptable, tolerate soils that are not too rocky and dry, but develop well only on the most fertile soils. A major insect problem is the ash gall mite which feeds on the male flowers, causing the flower clusters to develop irregularly branched galls that remain on the tree until spring. The vigor of the tree is not affected, but the galls can be unsightly. Control measures are unnecessary unless seed is required. White ash is subject to progressive decline, "ash yellows," caused by a phytoplasma. Borers, aphids and sawflies can be problematic, as can anthracnose, leaf spot and rust.
Uses:
Wood: The white ash is one of the most important broadleaf
timber trees in the US. The light brown wood is relatively lightweight,
hard, strong, tough but pliant, straight-grained and shock-resistant. It
is used for the long handles of rakes, hoes and shovels; baseball bats,
sporting goods and playground equipment; the bent parts of furniture; veneer
and paneling; boxes, crates and pallets; apiary and dairy containers; and
firewood. The strongest wood is obtained from young trees of second growth,
rather than from older specimens.
Wildlife: Seeds are eaten by wood ducks, turkeys, quail, grouse, finches, cardinals and other songbirds. White-tail deer feed on young twigs and leaves.
Horticulture: The white ash is more ornamental than the green ash, but is less popular due to its slower growth rate, potential size and susceptibility to pests and diseases. It is also less adaptable than the green ash. A Canadian introduction, 'Manitoo,' has a narrow, upright habit. 'Skyline' is a seedless form with good crotch angles and orange-red autumn foliage. 'Autumn Blaze' is a female cultivar with purple fall color, well adapted to prairie regions.
