white ash (Fraxinus americana)
Biltmore white ash
small-seed white ash
Fraxinus biltmoreana Beadle
CONFIRMATION STATUS: Confirmed.
TAXONOMY: The currently accepted scientific name of white
ash is Fraxinus americana L. Currently researchers recognize two
varieties of white ash: 1) Fraxinus americana var. americana and 2)
Fraxinus americana var. biltmoreana (Beadle) J. Wright. In addition,
a number of variants have been described within the species, but the
distinctions between these have not been generally confirmed.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERTICS: White ash is a native,
deciduous, long-lived tree. They grow up to 80 feet tall, maintaining a
central, straight, clear bole (particularly on good sites) in youth with an
even distribution of branches, developing a dense, conical or rounded
crown at maturity (older specimens can become as broad crowned as an
elm). When mature, the trunk is long, straight, and free of branches for
most of its length (except when open grown). Shade-killed branches drop
quickly-small ones within a year or two and larger ones within 4 or 5 years.
Leaves are compound, 8 to 15 inches (20-38 cm) in length, and usually
have seven oval, entire leaflets. White ash is dioecious. The male flowers
bloom first, before the leaf buds break. The pollen is already airborne
during the 7 to 10 days when the female flowers are receptive. The flowers
are borne in panicles near branch tips. White ash will start to flower when
it is 3 to 4 inches (8-10 cm) in d.b.h., but abundant flowering does not occur
until the tree is 8 to 10 inches (20-25 cm).
The bark is thick, dark ashy gray to brown in color, with uniform, interlacing
corky diamond-shaped ridges and furrow pattern. Older trees may be scaly.
The twigs of white ash are stout, gray-olive-green, hairless, with round
leaf scars at the bottom, notched at the top, with lateral buds in the notch.
The terminal bud is large, brown, with leathery scales and flanked by two
Leaves are deciduous, opposite, pinnately compound, 8 to 12 inches long,
leaflets usually 7 (5-9), short-stalked, ovate to ovate-lanceolate or elliptic,
acuminate, 6-13 cm long and 3-6 cm wide, sometimes with a few teeth
near the tip, dark green and smooth above, whitish below.
Flowers are numerous, very small, light green to purplish, in small branched
clusters near the branch tips, usually either male (staminate) or female
(pistillate), a single tree usually bearing only one sex (the species dioecious).
Female flowers occur in loose panicles, male flowers in tighter clusters,
appear after the leaves unfold. Both sexes lack petals.
Fruits are samaras 2.5-5 cm long, hanging in clusters with a narrow, single
wing extending about 1/3-1/4 of the way down the cylindrical body. The
samara are dry and flattened with a full, rounded, seed cavity, maturing in
fall and dispersing over winter. Almost 99 percent of the fruits (samaras)
contain one seed, about 1 percent contain two, and a very small percent
have twin embryos.
REGENERATION PROCESSES: White ash is dioecious; flowers
appear with or just before the leaves in April and May. A good seed crop is
produced about every third year. Good seeds are produced in all parts of
the crown. The time between the first noticeable enlargement of the male
flower buds until shedding is 2 to 3 weeks. Pollen shedding from an
individual tree usually takes 3 or 4 days. The pollen is carried by wind as
far as 100 in (328 ft) from the point of dispersion.
Female buds are completely open a few days after they begin to swell.
Exposed flowers remain receptive for about I week, but once the stigmas
discolor, the period of receptivity is past. Abundant seed crops are borne
by about half of the flowering trees.
White ash begins producing seed at a minimum age of 20 years. A good
seed crop is produced at intervals of 2-3 years, although the males flower
heavily each year. To best overcome dormancy, stratify under moist
conditions for 30 days at 14/30° C (night/ day) then for 60 days at 5° C.
A forest floor seed bank may retain viable white ash seeds for 3-4 years.
Germination can occur on mineral soil, humus, or leaf litter, and seedlings
develop best in partial sun. Mature trees may reach 200 years of age.
Stumps of freshly cut seedling and sapling white ash sprout readily. Usually
only one or two stems are produced. White ash resprouts from the root
crown after logging or fire. Sprouting ability decreases with age.
This species can be propagated by conventional methods of budding, grafting,
SITE CHARACTERISTICS: White ash has demanding soil fertility
and soil moisture requirements. These requirements may be provided
by soils derived from a variety of parent materials-limestone, basalt, shale,
alluvium, and fine glacial till. Best growth occurs on moderately well
drained soils, including areas underlain by compacted glacial till; light
textured, well drained, glacial drift; and sandy to clay loam soils in which
roots can penetrate to a depth of 40 cm (16 in) or more. It grows most
commonly on fertile soils with a high nitrogen content and a moderate to
high calcium content.
It is adaptable to a wide range of soil pH and prefers full sun. It rarely
forms pure stands. It occurs on middle slopes in the Northeast, on
slightly elevated ridges in the floodplains of major streams in the coastal
plain, and on slopes along major streams in the central states.
White ash is found in various topographic situations. It grows from near
sea level in the southeastern Coastal Plain to about 1050 m (3,450 ft) in
the Cumberland Mountains and up to 600 m (1,970 ft) in New York's
Adirondack Mountains. In the hilly and mountainous areas of the Northeast,
it grows on the mesophytic lower and middle slopes, usually stopping short
of both the dry, oak-pine ridgetops and the cold, spruce-fir mountain tops.
In the Coastal Plain, white ash usually is limited to the slightly elevated
ridges in the floodplains of major streams. In the Central States it is most
common on slopes along major streams, less common in upland situations,
and rarely found in the flat bottoms of major streams or in depressions.
Although rarely found in swamps, white ash is intermediately tolerant of
SUCCESSIONAL STATUS: White ash is primarily characteristic of early
and intermediate stages of succession. Throughout its range it is a minor
but constant component of both the understory and overstory of mature
forests on suitable soils.The seedlings are shade tolerant but can also
establish in full sun. Seedlings can survive under a canopy with less than 3
percent of full sunlight but grow little under these conditions. Seedlings that
receive sufficient sunlight grow rapidly. With increasing age, white ash
becomes less tolerant of shade and is classed overall as intolerant. The
decrease in shade tolerance with increasing age is reflected in the fact that
young white ash is abundant in the understory of northern hardwood
stands, but few grow into the overstory unless provided with light from
above. After persisting for a few years in moderately dense shade, trees
developing inside closed stands reach the overstory by responding quickly
to openings in the canopy.
White ash is a pioneer species that establishes itself on fertile abandoned
fields in several parts of the country. In the Southeast, much of the aban-
doned agricultural land is incapable of supporting white ash. On such
sites, white ash establishes itself only after some site protection and
improvement has been accomplished by pines. However, pioneer ash
often do not develop into good timber trees unless other hardwoods or
pines are also present to provide competition and reduce branchiness.
SEASONAL DEVELOPMENT: This species flowers in April-May, the
male first, before appearance of the leaves; fruiting August-October, the
seeds dispersed September-November. The pollen is already airborne
during the 7-10 days when the female flowers are receptive.
GENERAL DISTRIBUTION: White ash grows over most of eastern
North America, absent only from the outer Atlantic and Gulf coastal plains.
It occurs from Nova Scotia west to eastern Minnesota and south to Texas
and northern Florida, northward barely into southern Quebec and Ontario.
It is cultivated in Hawaii.
SKY MEADOWS DISTRIBUTION:
Tree specimens can be found on trails marked in red.
Appalachian Trail/Old Trail
South Ridge/North Ridge
Rolling Meadows/ Lost Mountain
HABITAT TYPES AND PLANT COMMUNITIES: Some of the
primary associates of white ash include eastern white pine (Pinus strobus),
northern red oak (Quercus rubra), white oak (Quercus alba), sugar maple
(Acer saccharum), red maple (Acer rubrum), yellow birch (Betula
alleghaniensis), American beech (Fagus grandifolia), black cherry (Prunus
serotina), American basswood (Tilia americana), eastern hemlock (Tsuga
canadensis), American elm (Ulmus americana), and yellow-poplar
(Liriodendron tulipifera). Understory shrubs and small trees frequently
found growing with ash are downy serviceberry (Amelanchier arborea),
pawpaw (Asimina triloba), American hornbeam (Carpinus caroliniana),
flowering dogwood (Cornus florida), witch-hazel (Hamamelis virginiana),
eastern hophornbeam (Ostrya virginiana), and mapleleaf viburnum
IMPORTANCE AND USES: White-tailed deer and cattle browse white
ash and beaver, porcupine, and rabbits may eat the bark of young trees.
The seeds are eaten by wood duck, northern bobwhite, turkey, grouse,
finches, grosbeaks, cardinals, fox squirrel, mice, and many other birds and
small mammals. The tendency of white ash to form trunk cavities makes
it valuable for cavity nesters such as redheaded, red-bellied, and pileated
woodpeckers. Once primary nest excavators have opened up the bole, it is
an excellent habitat for secondary nesters such as wood ducks, owls,
nuthatches, and gray squirrels.
White ash is a good tree for open areas such as parks and campuses; it
also is used as a lawn, shade, and street tree, even though its potential
large size can make it incongruous with a small area. It is an erect, graceful
tree, often with bronze-purple fall foliage. It is easy to transplant and
numerous cultivars have been developed, including seedless (male) forms.
Other selections are based on yellow to orange and purple fall colors,
persistence of leaves in the fall, height, crown shape (broadly to narrowly
oval) and density, growth vigor, and cold hardiness. White ash also has
been used in re-vegetating disturbed sites; it has been successfully used
in the reclamation of strip mines in Ohio, Kentucky, and Pennsylvania.
The wood of white ash is valued for its strength, hardness, heavy weight,
and elasticity (shock resistance). Native Americans appreciated its
usefulness for tools and implements, and it is used extensively today for
tool handles. Its use in wooden baseball bats is famous. The wood is also
used in furniture, doors, veneer, antique vehicle parts, railroad cars and
ties, canoe paddles, snowshoes, boats, posts, ties, and fuel. White ash is
the most valuable timber tree of the various ashes.
White ash was used by Native Americans for a variety of medicinal
purposes: a decoction of the leaves as a laxative and general tonic for
women after childbirth; the seeds as an aphrodisiac, a diuretic, an
appetite stimulant, a styptic, an emetic, and as a cure for fevers; and a
bark tea for an itching scalp, lice, snakebite, and other sores. Juice from
the leaves has been applied to mosquito bites for relief of swelling and
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