Identifying characteristics:
The green ash grows to 70 feet tall, has a broad, irregular or rounded
crown and a high, slender trunk. A great amount of variation occurs within
the species, making identification sometimes difficult. The pinnately-compound
leaves are opposite (rarely sub-opposite)
with narrowly winged leafstalks. Each leaf has 5 to 9 (usually 7) short-stalked,
elliptic to lance-shaped leaflets. The margins are conspicuously toothed
above the middle, and the leaf surface is dark, glossy green above and light
green and either glaucous or finely hairy underneath. In the fall, the leaflets
turn yellowish-brown and tend to fall one at a time. Male and female flowers are found on separate trees,
so some trees never bear fruit (males). The small, apetalous flowers are
produced in spring with or before the leaves. The male flowers occur in
short, compact panicles, the female flowers in loose panicles. The fruit is a narrow, 1- to 2-inch long,
paddle-shaped samara, with the wing extending along the upper half of the
slender seed cavity. Seed crops are abundant almost every year. The leaf
scars are semi-circular, with numerous closely-positioned bundle scars
forming a curved line. The buds are rounded, with 1 or 2 pairs of
visible, rust-brown scales. The thin bark
is gray-brown and slightly furrowed with firm, narrow ridges that intersect
to form a diamond pattern.
Similar species:
- black ash (F. nigra)
- white ash (F. americana)
- blue ash (F. quadrangulata)
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Ecology:
Distribution: This is the most widely distributed of all the native
US ashes. The range extends from Nova Scotia to Alberta in Canada, south
to Texas and northern Florida. This species is most abundant in the Mississippi
River Valley, and is native throughout Iowa.
Habitat: Although usually occurring on moist bottomlands, along stream banks and wet upland sites, it is extremely tolerant of climatic conditions, and can withstand heat, cold, droughts and floods. With wind-dispersed seeds that remain viable for years and germinate easily, this fast-growing species is common in fencerows, wood edges and uncultivated sites. Pests and diseases are seldom problematic to the green ash, but this species is somewhat susceptible to ash yellows, depending on which cultivar is planted. It becomes more susceptible to borers, canker and Verticillium wilt following drought or injury. Leaf diseases during wet spring weather may defoliate trees, but they usually recover. Ash flower mite galls sometimes cause the flowers of male trees to become deformed into unsightly brown growths that persist on the tree into winter.
Uses:
Wood: The green ash is an important timber tree. The wood
is often sold as white ash (F. americana) which is being supplanted
by this species in industry as it becomes more scarce. The wood of green
ash is heavier, but it has the same strength, elasticity, and straight grain
as that of white ash. It is used for tool handles, paddles and oars, snowshoes,
tennis rackets and picture frames.
Wildlife: Large seed crops make this an important food source for turkey, quail, cardinals, finches, woodchucks, squirrels and other rodents. Deer and moose browse the young shoots and foliage.
Horticulture: This is one of the most adaptable native trees for planting as a street or lawn tree in Iowa. It provides good shade and is a fast grower. It is a good reforestation tree for sites where the soil is not too dry. Some botanists classify those trees with glabrous twigs and leaves as the variety subintegerrima; and those with pubescent twigs and undersides of leaves, with thinner leaflets, as the variety pennsylvanica (red ash).
