dcsimg

Comments

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Ulmus americana is reported as widely escaped in Idaho, which is not part of the natural range of this taxon. It is occasionally cultivated outside its native distribution, and it has escaped sporadically from cultivation. It is also reported as naturalized in Arizona, but I have seen no specimens.

Ulmus americana is the state tree for Massachusetts and for North Dakota.

The American elm is susceptible to numerous diseases, including Dutch elm disease. Ulmus americana has been a street and shade tree of choice because of its fast growth and pleasant shape and size. The species still exists in substantial numbers both as shade trees and in nature.

Numerous infraspecific taxa have been recognized in Ulmus americana (A. J. Rehder 1949; P. S. Green 1964).

Native American tribes frequently used parts of Ulmus americana for a variety of medicinal purposes, including treatment of coughs and colds, sore eyes, dysentary, diarrhea, broken bones, gonorrhea, and pulmonary hemorrhage, as a gynecological aid, as a bath for appendicitis, and as a wash for gunwounds (D. E. Moerman 1986).

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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
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Flora of North America Vol. 3 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Description

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Trees , 21-35 m; crowns spreading, commonly vase-shaped. Bark light brown to gray, deeply fissured or split into plates. Wood soft. Branches pendulous, old-growth branches smooth, not winged; twigs brown, pubescent to glabrous. Buds brown, apex acute, glabrous; scales reddish brown, pubescent. Leaves: petiole ca. 5 mm, glabrous to pubescent. Leaf blade oval to oblong-obovate, 7-14 × 3-7 cm, base oblique, margins doubly serrate, apex acute to acuminate; surfaces abaxially glabrous to slightly pubescent, tufts in axils of veins, adaxially glabrous to scabrous. Inflorescences fascicles, less than 2.5 cm, flowers and fruits drooping on elongate pedicels; pedicel 1-2 cm. Flowers: calyx shallowly lobed, slightly asymmetric, lobes 7-9, margins ciliate; stamens 7-9; anthers red; stigmas white-ciliate, deeply divided. Samaras yellow-cream when mature, sometimes tinged with reddish purple (s range of species), ovate, ca. 1 cm, narrowly winged, margins ciliate, cilia yellow to white, to 1 mm. Seeds thickened, not inflated. 2 n = 56.
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
bibliographic citation
Flora of North America Vol. 3 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Flora of North America @ eFloras.org
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Flora of North America Editorial Committee
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Distribution

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Man., N.B., N.S., Ont., P.E.I., Que., Sask.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Tex., Vt., Va., W.Va., Wis., Wyo.
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
bibliographic citation
Flora of North America Vol. 3 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Flowering/Fruiting

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Flowering winter-early spring.
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
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Flora of North America Vol. 3 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Habitat

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Alluvial woods, swamp forests, deciduous woodlands, fencerows, pastures, old fields, waste areas; planted as street trees; 0-1400m.
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
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Flora of North America Vol. 3 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Synonym

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Ulmus americana var. aspera Chapman; U. americana var. floridana (Chapman) Little; U. floridana Chapman
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
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Flora of North America Vol. 3 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Brief Summary

provided by EOL authors
The American Elm (Ulmus americana) is a native North American tree in the Ulmaceae family. Growing quickly when young, the American Elm has a broad or upright, vase-shaped silhouette, 80 to 100 feet high and 60 to 120 feet wide. Trunks on older trees can reach to seven feet across. Trees have an extensive but shallow root system. Propagation is by seed or cuttings; young plants transplant easily. The six inch long, deciduous, double serrated leaves are dark green throughout the year, fading to yellow before dropping in fall. In early spring, before the new leaves unfold, its rather inconspicuous small green flowers appear on pendulous stalks. These blooms are followed by green, wafer-like seedpods which mature soon after flowering is finished. The seeds are quite popular with both birds and wildlife. American Elms must be at least 15 years old before they will bear seed. The wood of American Elm is very hard and was a valuable timber tree used for lumber, furniture and veneer. Native Americans once made canoes out of American Elm trunks, and early settlers would steam the wood so it could be bent to make barrels and wheel hoops. Once a very popular and long-lived (300+ years) shade and street tree, American Elm suffered a dramatic decline with the introduction of Dutch elm disease, a fungus spread by a bark beetle. It is vital to the health of existing trees that a program of monitoring be in place to administer special care to these disease- and pest-sensitive trees.

Common Names

provided by Fire Effects Information System Plants
American elm
white elm
water elm
soft elm
Florida elm
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Cover Value

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More info for the term: cover

American elm trees provide thermal cover and nesting sites for a variety
of primary and secondary cavity nesters [26,30].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Description

provided by Fire Effects Information System Plants
More info for the terms: forest, fruit, perfect, tree

American elm is a deciduous, fast-growing, long-lived tree which may
reach 175 to 200 years old with some as old as 300 years [5,27,53]. In
dense forest stands, American elm may reach 100 to 200 feet (30-36 m) in
height and 48 to 60 inches (122-152 cm) in d.b.h. Heights of 80 feet
(24 m) are common on medium sites but on very wet or very dry soils, the
species is often 40 to 60 feet (12-18 m) tall at maturity [5,44,54]. In
the forest American elm often develops a clear bole 50 to 60 feet (15-18
m) in length. Open-grown trees fork 10 to 20 feet (3-6 m) from the
ground with several erect limbs forming a wide, arching crown [29,56].
The alternate, double-toothed leaves are 2 to 5 inches (5-10 cm) long
and 1 to 3 inches (2.5-7.5 cm) wide. The dark gray bark is deeply
furrowed (9,15). The perfect flowers are borne in dense clusters of
three or four fascicles. The fruit is a samara consisting of a
compressed nutlet surrounded by a membranous wing [7,29].

The root system of American elm varies according to soil moisture and
texture. In heavy, wet soils the root system is widespreading, with
most of the roots within 3 to 4 feet (1.0 - 1.2 m) of the surface. On
drier soils, American elm develops a deep taproot [29].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Distribution

provided by Fire Effects Information System Plants
The typical variety of American elm (var. americana) is found throughout
eastern North America [5]. Its range extends from southern Newfoundland
westward through southern Quebec and Ontario, northwest through Manitoba
into eastern Saskatchewan, then south on the upper floodplains and
protected slopes of the Dakotas. It is found in the canyons and
floodplains of northern and eastern Kansas and in eastern Oklahoma and
central Texas. American elm is common along the Gulf Coast and east
into central Florida [9,7,29,43].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Fire Ecology

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More info for the terms: fire regime, seed

Fire rarely occurs in the moist areas where American elm typically
grows. When fire does occur and conditions are dry, American elm
greatly decreases following fire [12]. Wind- and water-dispersed seed
are important in the survival of American elm following fire [28].
After being top-killed, young American elm will sprout from the base
following fire [5].

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Fire Management Considerations

provided by Fire Effects Information System Plants
More info for the term: top-kill

Fire is usually not a major management consideration for American elm in
the North, but in the southern bottomlands, fall and early spring fires
are extremely damaging. Most fires will top-kill seedlings and saplings
and wound larger trees, providing an entry point for heart-rot fungi
[20,40].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Growth Form (according to Raunkiær Life-form classification)

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Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Habitat characteristics

provided by Fire Effects Information System Plants
More info for the terms: cover, swamp

American elm is common on wet flats and bottomlands but is not
restricted to these sites. In the southern bottomland regions, it
commonly occurs on terraces and flats but not in deep swamps. At higher
elevations in the Appalachians it is often limited to the vicinity of
larger streams and rarely occurs at elevations above 2,000 feet (610 m).
In the Lake States and Central States, it is found on plains and moraine
hills as well as the bottomlands and swamp margins. Along the
northeastern edge of its range, it is usually restricted to valleys
along waterways except where it has been planted on the uplands
[29,42,50].

American elm grows best on rich, well-drained loams. Growth is poor on
dry sands and where the summer water table is constantly high. In
Michigan, on loam and clay soils, growth is good when the summer water
table drops 8 to 10 feet (2.4-3.0 m) below the surface. In the South,
American elm is common on clay and silty-clay loams on bottomlands and
terraces. Growth is medium on wetter sites and good on well-drained
sites. In the arid western end of its range, American elm is restricted
to silt or clay loams in river bottoms and terraces. American elm most
commonly grows on soils of the orders Alfisols, Inceptisols, Mollisols,
and Ultisols [5,29,41].

In addition to those species mentioned in SAF Cover Types, common
associates of American elm include balsam fir (Abies balsamea), silver
maple (Acer saccharinum), sycamore (Platanus occidentalis), pin oak
(Quercus palustris), black tupelo (Nyssa sylvatica), white ash (Fraxinus
americana), sweetgum (Liquidambar styraciflua), hackberry (Celtis
occidentalis), boxelder (Acer negundo), birch (Betula spp.), and hickory
(Carya spp.) [4,19,43,50].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Habitat: Cover Types

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More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the terms: hardwood, swamp

16 Aspen
24 Hemlock - yellow birch
25 Sugar maple - beech - yellow birch
26 Sugar maple - basswood
28 Black cherry - maple
39 Black ash - American elm - red maple
42 Bur oak
46 Eastern redcedar
52 White oak - black oak - northern red oak
53 White oak
55 Northern red oak
60 Beech - sugar maple
62 Silver maple - American elm
63 Cottonwood
85 Slash pine - hardwood
91 Swamp chestnut oak - cherrybark oak
92 Sweetgum - willow oak
93 Sugarberry - American elm - green ash
94 Sycamore - sweetgum - American elm
95 Black willow
96 Overcup oak - water hickory
101 Baldcypress
102 Baldcypress - tupelo
103 Water tupelo - swamp tupelo
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Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Habitat: Ecosystem

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More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

FRES10 White - red - jack pine
FRES11 Spruce - fir
FRES15 Oak - hickory
FRES16 Oak - gum - cypress
FRES17 Elm - ash - cottonwood
FRES18 Maple - beech - birch
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Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Habitat: Plant Associations

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More info on this topic.

This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: forest

K093 Great Lakes spruce - fir forest
K095 Great Lakes pine forest
K096 Northeastern spruce - fir forest
K100 Oak - hickory forest
K101 Elm - ash forest
K111 Oak - hickory - pine forest
K112 Southern mixed forest
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Immediate Effect of Fire

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More info for the terms: severity, top-kill

American elm is easily damaged by fire [11]. Low- and moderate-severity
fires top-kill trees up to sapling size and will wound larger trees
[29]. In a study of the fire effects on 2- to 8-year old American elm
trees in the Missouri prairie, two spring fires of unreported severity
in March and April caused dieback of 40 and 90 percent, respectively
[33].

American elm suffered complete tissue death when the cambium was exposed
to a temperature of 140 degrees Fahrenheit (60 deg C) for 20 minutes
[31].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Importance to Livestock and Wildlife

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More info for the term: fruit

Although American elm is not considered a preferred browse, deer,
rabbits, and hares will occasionally browse the leaves and twigs
[24,49]. The seeds are eaten by a number of small birds. The
flowerbud, flower, and fruit are eaten by mice, squirrels, oppossum,
ruffed grouse, northern bobwhite, and Hungarian partridge [5].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Life Form

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More info for the term: tree

Tree
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Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Management considerations

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More info for the terms: natural, tree

American elm has suffered greatly since the introduction of Dutch elm
disease from Europe around 1930. Since then the disease has spread over
much of the United States [46,48]. The disease is caused by the fungus
Ceratocystis ulmi. Spores of this fungus are carried by American
(Hylurgopinus rufipes) and European bark beetles (Scolytus multistria)
from diseased trees to healthy trees. The beetles breed only in dead,
dying, or recently cut elm wood and winter as larvae under the bark. In
the spring, adults emerge and fly a short distance (usually less than
500 feet [150 m]) to feed in the twig crothes or small branches in the
upper parts of the living trees. As the beetles feed, the spores are
introduced into the tree and the tree becomes diseased. After the
spores have been introduced into the tree's vascular system, the xylem
becomes plugged and a toxin is produced. The trees wilt on the small
branches and eventually on the whole limbs [16,39,47]. A program for
controlling Dutch elm disease has been described [47].

Most of the genetic research of elm has been concerned with the
resistance of various species, varieties, races, and hybrids to Dutch
elm disease or phloem necrosis. Natural hybridization in American elm
is uncommon, although controlled crosses have been made with Siberian
elm (Ulmus pumila). However, the success of these controlled crosses
has been quite poor [2,29]. American elm is a tetraploid, having 28
chromosomes, while most other elms have 14 chromosomes, making it
difficult to cross with other elms [35].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Occurrence in North America

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AL AR CT DE FL GA HI IL IN KS
KY LA ME MD MA MI MN MS MO NE
NH NJ NY NC ND OH OK PA RI SC
SD TN TX VT VA WV WI MB NB NF
ON PQ SK
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Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Other uses and values

provided by Fire Effects Information System Plants
Before the advent of Dutch elm disease, American elm was prized as a
street ornamental in many cities in North America [55]. The inner bark
of American elm was used in various decoctions by the Native Americans
in the southeastern United States [17].
license
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Phenology

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More info on this topic.

More info for the terms: fruit, seed

The time of flowering, seed ripening, and seed fall varies by about 100
days between the Gulf Coast and Canada. The flower buds swell early in
February in the South and as late as May in Canada. The trees are in
flower 2 to 3 weeks before the leaves unfold. The fruit ripens as the
leaves unfold or soon afterward. The seed is dispersed as it ripens and
seed fall is usually complete by the middle of March in the South and by
the middle of June in the North [3,7,29].
license
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Plant Response to Fire

provided by Fire Effects Information System Plants
Young American elm will sprout from the base following fire [1,25].

The Research Paper by Bowles and others 2007 provides information on
postfire responses of several plant species, including American elm,
that was not available when this species review was originally written.
license
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Post-fire Regeneration

provided by Fire Effects Information System Plants
More info for the terms: secondary colonizer, seed

Tree with adventitious-bud root crown/root sucker
Secondary colonizer - on-site seed
Secondary colonizer - off-site seed
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Regeneration Processes

provided by Fire Effects Information System Plants
More info for the terms: epigeal, seed, stratification, tree

Seed production and dissemination: American elm seed production may
begin as early as age 15 but is seldom abundant before age 40. When
mature, American elm is a prolific seed producer. Trees as old as 300
years have been reported to bear seed [5]. In closed stands, seed
production is greatest in the exposed tops of trees. The winged seeds
are light and readily disseminated by the wind. Although most seeds
fall within 300 feet (90 m) of the parent tree, some may be carried 0.25
mile (0.4 km) or more. In riverbottom stands, the seeds may be carried
by the water for miles. Cleaned, unwinged seeds average 70,900 per
pound (156,000/kg) [28,46,53].

Seedling development: Germination in American elm is epigeal. Seeds
usually germinate soon after they fall, although some seeds remain
dormant until the following spring. Germination is usually 6 to 12 days
but may extend over a period of 60 days. Dormancy may be overcome by
stratification in sand for 60 days at 41 degrees Fahrenheit (5 deg C).
The seeds germinate best with night temperatures of 68 degrees
Fahrenheit (20 deg C) and day temperatures of 86 degrees Fahrenheit (30
deg C). The germination capacity averages about 65 percent
[7,10,29,46].

Vegetative reproduction: American elm will reproduce fairly vigorously
by stump sprouts from small trees. Large trees 150 to 250 years old
seldom sprout after cutting [29]. Observations in undisturbed
bottomlands of Minnesota suggest that replacement of American elm may be
by root suckering [5].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Regional Distribution in the Western United States

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More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

16 Upper Missouri Basin and Broken Lands
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Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Successional Status

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More info on this topic.

More info for the terms: climax, hardwood

Faculative Seral Species.

American elm is classed as intermediate in tolerance among eastern
hardwoods [50]. It usually responds well to release. Once it becomes
dominant in a mixed hardwood stand, it is seldom overtaken by the other
species. It can persist for years as an intermediate but will be
replaced by tolerant hardwoods such as sugar maple (Acer saccharum) or
beech (Fagus grandifolia) if suppressed. Although American elm is not
listed as a key species in the climax types on moist sites, it is
usually one of the associated species [29,32].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Taxonomy

provided by Fire Effects Information System Plants
The currently accepted scientific name for American elm is Ulmus
americana L. [36]. Recognized varieties include U. americana var.
americana and U. americana var. floridana, which is restricted to the
coastal plains from eastern North Carolina to central Florida [15,27].
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Value for rehabilitation of disturbed sites

provided by Fire Effects Information System Plants
American elm can be planted for erosion protection and as a windbreak
[21,38]. Its shallow and widespreading roots make it fairly windfirm
[8,56]. American elm can be propagated by cuttings, but the results
have been variable. Doran [14] reports that cuttings taken in June were
rooted with 94 percent success after treatment with indolebutyric acid
but rooted poorly with no treatment. The propagation of root cuttings
was ineffective for American elm in Ohio [6]. Leafbud cuttings are
superior to soft-wood cuttings for propagating American elm [23].
license
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bibliographic citation
Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Wood Products Value

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More info for the term: fuel

The wood of American elm is coarse-grained, heavy, and strong. It lacks
durability, warps, and splits badly in seasoning [44]. The wood is
used in the manufacture of boxes, baskets, crates, barrels, furniture,
agricultural implements, and caskets. Elm veneer is used for furniture
and decorative panels [9,51]. American elm is also used for fuel wood
[13].
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Coladonato, Milo. 1992. Ulmus americana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Associations

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Recently it has been decimated by Dutch Elm Disease. (Hultman, 1978) This introduced pathogen, Ophiostoma ulmi hit city trees particularly fiercely. Dutch Elm Disease is spread by a beetle typically and is a fungus. Snags with peeling bark from the disease may produce valuable wildlife cover. Gray and fox squirrels feed heavily on flower buds. Fallen mature seeds are used by small rodents and wood ducks. Foliage is taken by white-tailed deer and woodchucks. Cover is used by nesting shrubland birds. (Weeks et al, 2005) Population was ravaged by the Dutch Elm disease, caused by a fungus introduced accidentally about 1930 and spread by European and native elm bark beetles. (NPIN, 2008)

Wildlife uses include seed eating by granivorous birds, bird cover, bird nesting sites, and substrate for insectivorous birds. Seeds feed small mammals. It is a larval host for Mourning Cloak (Nymphalis antiopa), Columbia silkmoth (Hyalophora columbia), Question Mark (Polygonia interrogationis), Painted Lady (Vanessa cardui), and Eastern Comma (Polygonia comma). (NPIN, 2008)

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Cyclicity

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Active growth period is Spring and Summer, and is rapid. The tree is deciduous. Blooming occurs in Early Spring. Fruit/seed period begins in Spring and ends in Spring. (USDA PLANTS, 2009) Flowering occurs in April and May. (Peattie, 1930) Flowering is March to May. Seeds are produced April to May. (Hultman, 1978) Fall coloration is yellow. Large flowers may appear in February further South. (Weeks et al, 2005) Bloom time is February, March, and April. (NPIN, 2008)
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Distribution

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This is the most common elm in the eastern US. (Weeks et al, 2005) The tree is reported as widely escaped in Idaho, which is not part of the natural range. It is occasionally cultivated outside its native distribution, and it has escaped sporadically from cultivation. It is also reported as naturalized in Arizona. (FNA, 2006)

USA: AL , AR , CT , DE , FL , GA , IL , IN , IA , KS , KY , LA , ME , MD , MA , MI , MN , MS , MO , MT , NE , NH , NJ , NY , NC , ND , OH , OK , PA , RI , SC , SD , TN , TX , VT , VA , WV , WI , WY , DC (NPIN, 2008)

Canada: MB , NB , NS , ON , PE , QC , SK (NPIN, 2008)

Native Distribution: N.S., s. Man & s.e. Sask. & Crook Co. WY, s. to FL & c. TX (NPIN, 2008)

USDA Native Status: L48(N), CAN(N) (NPIN, 2008)

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Genetics

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2 n = 56. (FNA, 2006)
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Habitat

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Habitat constitutes rich meadows and stream bottoms along morainal borders. Occasional in red maple swamps back of high dunes. (Peattie, 1930) Most common in bottomlands. (Hultman, 1978) Common in moist to wet, rich woods and flood-plains. (Weeks et al, 2005) Native habitat consists of stream banks and lowland areas. (NPIN, 2008) Habitat includes alluvial woods, swamp forests, deciduous woodlands, fence-rows, pastures, old fields, and waste areas. It is also planted as street trees. Elevation from 0-1400 m. (FNA, 2006)
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Life Expectancy

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Lifespan is moderate. (USDA PLANTS, 2009) Formerly it was long-lived. Trees to 400 years old have been documented. It now rarely survives to maturity at 150 years of age because of Dutch Elm Disease. (Weeks et al, 2005)
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Morphology

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Overall This is an erect tree. (USDA PLANTS, 2009) The tree is tall with an umbrella-shaped crown. (Peattie, 1930) Large trees are easily recognized by tall, clear trunks, open, spreading crowns, and graceful, drooping limbs that form a vase shape. It often has a buttressed base. (Weeks et al, 2005) This tree can develop three distinct habits including the vase-shaped form in which the trunk divides into several erect limbs strongly arched above and terminating in numerous slender, pendulous branchlets. A more wide-spreading and less arching form occurs, as well as a narrow form with branchlets clothing the entire trunk. This is a large, handsome, graceful tree, often with enlarged buttresses at base. (NPIN, 2008)

Flowers are green. (USDA PLANTS, 2009) Flowers are borne in axils on the old twigs. Calyx is bell-shaped and 4-9-lobed. Flowers hang on long drooping pedicels. (Peattie, 1930) Flowers bloom in clusters along the stem. (Hultman, 1978) They have no petals. (Weeks et al, 2005) Bloom color is red or green. (NPIN, 2008) Flowers are born on a shallowly lobed calyx. They are slightly asymmetric, with 7-9 lobes and ciliate margins. There are 7-9 stamens. Anthers are red and stigmas are white-ciliate and deeply divided. (FNA, 2006)

Fruit is brown. (USDA PLANTS, 2009) The samara (winged fruit) is rounded, the wing continuous all around except at the apex. Fruit may be oval or ovate, and is ciliate with fine hairs on the margins. (Peattie, 1930) Single seeds are each surrounded by a papery wing. (Hultman, 1978) Fruit is round and flat with hairy margins. The tip is deeply notched. (Weeks et al, 2005) The fruit is a yellowish to cream samara with narrow wings and hairy edges. Seeds are thick but not inflated. (UW, 2009) Samaras are yellow-cream when mature, though sometimes tinged with reddish purple (particularly in the Southern range of species). They are arrowly winged, with ciliate margins. Cilia are yellow to white. (FNA, 2006)

Leaves are green and coarse. (USDA PLANTS, 2009) Leaves are obovate-oblong and abruptly pointed. Leaves are oval, unequal-sided at the base, and sharply doubly serrate. They are rough above, dull green, and paler below. (Peattie, 1930) Elliptical with a coarsely double-toothed edge, and tapering to a point. (Hultman, 1978) Simple leaves that have a lop-sided base. Fall coloration is yellow. (Weeks et al, 2005) Dark-green leaves have variable fall color. (NPIN, 2008)

Stems This tree has a single stem growth habit. (USDA PLANTS, 2009) Erect arching branches form an umbrella-shaped crown. Twigs and buds are smooth or sparingly pubescent. (Peattie, 1930) Alternate branching is typical. Buds are elongate with chestnut-brown, slightly hairy scales. Twigs zig-zag from node to node. Lateral leaf buds lie against the twig. (Weeks et al, 2005) usually forked into many spreading branches, drooping at ends, forming a very broad, rounded, flat-topped or vaselike crown, often wider than high. (UW, 2009) Old-growth branches are smooth and not winged. Twigs are brown and pubescent to glabrous. (FNA, 2006)

Bark is flaky and gray. (Peattie, 1930) Bark is gray and tough. (Hultman, 1978) Bark is spongy until mature, and is tannish gray with thick, interlacing ridges. Inner bark is two-toned with light and dark layers. It is tan colored and spongy when young. (Weeks et al, 2005)

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Size

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Tree height at 20 years is a maximum of 50' tall, at maturity 120.0' tall. (USDA PLANTS, 2009) Tree may be 50-100' tall. (Hultman, 1978) The tree was once 100'+ regularly, but is now more commonly 30-40'. (Weeks et al, 2005) It usually grows 60-80'. (NPIN, 2008)

Flowers inflorescence is less than 1" hanging cluster. (UW, 2009) Fascicles are less than 2.5 cm and the pedicel is 1-2 cm. (FNA, 2006)

Fruit is ovate and roughly 1 cm. Cilia to 1 mm. (FNA, 2006)

Leaves 4-6" long. (Hultman, 1978) Petiole is roughly 5 mm. Leaves are 7-14 × 3-7 cm. (FNA, 2006)

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Uses

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The tree can be harvested commercially for lumber products, naval store products, and pulpwood products. (USDA PLANTS, 2009) A valuable timber tree much planted for ornament though generally not the best to stand the fumes of some cities. Its branches meet across the road in a vaulted arch that permits the passage of high vehicles. (Peattie, 1930) It was used for years as an ornamental, and was once the most common shade tree in America. Recently it has been decimated by Dutch Elm Disease. (Hultman, 1978) Research is underway to produce disease-resistant cultivars for reintroduction in landscaping uses. (Weeks et al, 2005) This well-known, once abundant species, was familiar on lawns and city streets throughout America. The wood is used for containers, furniture, and paneling. Because of its fundamental architectural form, this is an ideal street tree. Because it is relatively odourless, the wood was used to make crates and barrels for cheeses, fruits and vegetables. (NPIN, 2008) Ulmus americana is the state tree for Massachusetts and for North Dakota. (FNA, 2006)

Various preparations of bark were used by pregnant women to insure stability of children, for menstrual cramps, for colds, for severe coughs, for dysentery, for "summer disease-vomiting, diarrhea and cramps," to facilitate childbirth and for parturition, for broken bones, for appendicitis, for sore eyes as an eye lotion, for gonorrhea, and for pulmonary hemorrhage. An infusion of root bark was taken for excessive menstruation. Wood was used in various capacities as a structural and vessel building material. (UM, 2009)

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Associated Forest Cover

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Throughout its range, American elm seldom grows in pure stands and is usually found in mixture with other species. It is a major component of four forest cover types: Black Ash-American Elm-Red Maple (Society of American Foresters Type 39), Silver Maple-American Elm (Type 62), Sugarberry-American Elm-Green Ash (Type 93), and Sycamore-Sweetgum-American Elm (Type 94). It is a minor component in 20 other forest types.

Black Ash-American Elm-Red Maple (Type 39) appears throughout the Northern Forest and into the Boreal Forest in Canada, and throughout the Lake States and into the northern edge of the Central Forest. In this type the most common associates, other than the type species, are as follows: In the Lake States and Canada, balsam poplar (Populus balsamifera), balsam fir (Abies balsamea), and yellow birch (Betula alleghaniensis); in Ohio and Indiana, silver maple (Acer saccharinum), swamp white oak (Quercus bicolor), sycamore (Platanus occidentalis), pin oak (Quercus palustris), black tupelo (Nyssa sylvatica), and eastern cottonwood (Populus deltoides); in New England and eastern Canada, sweet birch (Betula lenta), paper birch (B. papyrifera), gray birch (B. populifolia), silver maple, and black spruce (Picea mariana); and in New York, white ash (Fraxinus americana), slippery and rock elms (Ulmus rubra and U. thomasii), yellow birch, black tupelo, sycamore, eastern hemlock (Tsuga canadensis), bur oak (Quercus macrocarpa), swamp white oak, and silver maple.

Silver Maple-American Elm (Type 62) is common throughout the Central Forest and extends into Canada. Major associates in this type are sweetgum (Liquidambar styraciflua), pin oak, swamp white oak, eastern cottonwood, sycamore, green ash (Fraxinus pennsylvanica), and other moist site hardwoods.

Sugarberry-American Elm-Green Ash (Type 93) is found throughout the Southern Forest within the flood plains of the major rivers. Hackberry (Celtis occidentalis) replaces sugarberry (C. laevigata) in the northern part of the range. Major associates are water hickory (Carya aquatica), Nuttall (Quercus nuttallii), willow (Q. phellos), water (Q. nigra), and overcup (Q. lyrata) oak, sweetgum, and boxelder (Acer negundo).

Sycamore-Sweetgurn-American Elm (Type 94) appears as scattered stands throughout the Southern Forest region and lower Ohio River Valley. Common associates include green ash, sugarberry, hackberry, boxelder, silver maple, cottonwood, black willow (Salix nigra), water oak, and pecan (Carya illinoensis).

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Climate

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Within the natural range of American elm, the climate varies from warm and humid in the southeast to cold and dry in the northwest. Average temperatures are as follows: January, from -18° C (0° F) and below in Canada and 16° C (60° F) in central Florida; July, from 16° C (60° F) in Manitoba to 27° C (80° F) in the Southern States; annual maximum, 32° C (90° F) to 35° C (95° F) in the Northeast and 38° C (100° F) to 41° C (105° F) in the South and West; annual minimum, from -40° C (-40° F) to -18° C (0° F) in the North and -18° C (0° F) to -1° C (30° F) in the South.

Average annual precipitation varies from a scarce 380 min (15 in) in the Northwest to a plentiful 1520 mm (60 in) on the gulf coast. Over the central part of the species range there are about 760 to 1270 min (30 to 50 in) per year. Throughout the range most of the precipitation comes during the warm (April-September) season. Average annual snowfall generally varies from none in Florida to about 200 cm (80 in) in the Northeast. A few areas, mainly around the Great Lakes, get 254 to 380 cm (100 to 150 in) of snow per year.

The average frost-free period is about 80 to 160 days for the northern tier of States and Canada to about 200 to 320 days for the gulf coast and Southeastern States.

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Damaging Agents

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Since 1930, when Dutch elm disease reached the United States in a shipment of elm logs from Europe, it has spread to 41 States from coast to coast. The causal fungus, Ceratocystis ulmi, is introduced into the sap stream of twigs or small branches during feeding by the smaller European elm bark beetle, Scolytus multistriatus, and the native elm bark beetle, Hylurgopinus rufipes. Dutch elm disease is characterized by a gradual wilting and yellowing of the foliage, usually followed by death of the branches and eventually the whole tree (5,14).

In addition to Dutch elm disease, several other diseases also are responsible for losses in shade and forest elms. Phloem necrosis, caused by a virus (Morsus ulmi) is detected by flagging or browned leaves and butterscotch-colored phloem with a wintergreen odor. It is transmitted by the whitebanded elm leafhopper (Scaphoideus luteolus) and through root grafts. Trees usually die within a year after symptoms appear. Verticillium wilt (Verticillium albo-atrum) is soil borne and usually enters host plants through the roots. Trees show dieback symptoms similar to Dutch elm disease (10). Other diseases include diebacks caused by Cephalosporium spp. and Dothiorella ulmi; a leaf black spot (Gnomonia ulmea); twig blight (Cytosporina ludibunda); cankers (Nectria spp., Sphaeropsis ulmicola, and Phytophthora inflata); elm wetwood (Erwinia nimipressuralis); and elm mosaic virus (3,4). Some of the common wood rot fungi are Pleurotus ulmarius, P. ostreatus, Armillaria mellea, Ganoderma applanatum, Phellinus igniarius, and numerous species of Polyporus.

American elm is attacked by hundreds of insect species including defoliators, bark beetles, borers, leaf rollers, leaf miners, twig girdlers, and sucking insects. The carpenterworm (Prionoxystus robinae) bores into the sapwood and degrades the wood. Among the insects that defoliate elm are the spring cankerworm (Paleacrita vernata), the forest tent caterpillar (Malacosoma disstria), the elm leaf beetle (Pyrrhalta luteola), the whitemarked tussock moth (Orgyia leucostigma), the elm spanworm (Ennomos subsignaria), and many other leaf-eating insects that attack elm and other hardwoods. The elm cockscombgall aphid (Colopha ulmicola) forms galls on the leaves but does little damage to the tree. Several scale insects attack elm and may cause damage. Both the elm scurfy scale (Chionaspis americana) and the European elm scale (Gossyparia spuria) are widely distributed. Among the leafhoppers, the whitebanded elm leafhopper is classed as a serious pest since it is the vector for phloem necrosis (15).

Besides insect and disease losses, animal damage, and fire, climatic factors also can have an impact on survival and growth of American elm. Young forest trees may sunscald when exposed by harvesting or thinning operations. Open-grown American elm forks and develops a widespread crown that is susceptible to injury by heavy, wet snows and glaze storms. Of 37 tree species examined after an ice storm in Illinois, American elm ranked fourth in susceptibility to ice damage. In dense stands, such injuries are less severe and are not generally a management problem. Although American elm is shallow rooted in wet soils, it is fairly windfirm because the roots are widespread.

The species is reasonably drought resistant, but prolonged drought reduces growth and may cause death. During the drought of 1934, in the Midwest prairie region, losses of American elm and associated species ran as high as 80 to 90 percent. The 1951-54 drought also caused severe losses in the bottom lands of the South where American elm was more susceptible to drought than the lowland red oaks. Prolonged spring floods may cause death or growth loss. Despite suitable temperatures, in Minnesota bottom lands root elongation does not begin until the spring floods recede and soil aeration increases. On these sites and where trees are planted between street and sidewalk, buttress roots often are a result of inadequate soil aeration.

Fire damage is not a major management problem in the North; however, in southern bottom lands, fall and sometimes early spring fires are extremely damaging. Fires can kill seedling- and sapling-size trees and wound larger trees, thus admitting heartrot fungi.

Animal damage to American elm, from the sapling stage to maturity, is not a serious problem except for sapsucker injury that degrades the wood.

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Flowering and Fruiting

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The process of flowering, seed ripening and seed fall in American elm takes place in the spring throughout the range. The glabrous flower buds swell early in February in the South and as late as May in Canada. The flowers appear 2 to 3 weeks before leaf flush. Soon after wind pollination occurs, the fruit ripens, and seed fall is usually complete by mid-March in the South and mid-June in the North.

American elm flowers are typically perfect and occur on long, slender, drooping pedicels, about 2.5 cm (1 in) long, in 3- or 4-flowered short-stalked fascicles. The anthers are bright red, the ovary and styles are light green, and the calyx is green tinged with red above the middle. With controlled pollinations, floral receptivity is greatest when stigma lobes are reflexed above the anthers. The trees are essentially self-sterile. A test in Canada showed only 1.5 percent viable seed from self-pollinated flowers. Pollination may be hampered in a wet spring since the flower anthers will not open in a saturated atmosphere (9).

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Genetics

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The study of genetics in American elm has been primarily directed toward combining resistance to Dutch elm disease with desirable growth Characteristics. Only a few selections from American elm look promising at this time. Noteworthy is the "American Liberty" elm, a multiclonal variety selected from second-generation crosses of the most resistant parents. Despite high selection intensity, their resistance is still inferior to resistant cultivars derived from Asian or European sources.

A few horticultural forms have been recognized. These are Ulmus americana columnaris, a form with a narrow columnar head, U. americana ascendens, with upright branches, and U. americana pendula, with long pendulous branches.

Hybridization within the genus Ulmus has been aimed primarily at breeding for Dutch elm disease and phloem necrosis resistance. Because of the difficulty of hybridizing American elm, which has a chromosome number twice that of all the other elms (56 versus 28), most of the breeding and selection work does not include American elm. Thousands of attempts to cross the American with the Siberian elm have failed. Reports of successful artificial hybridization and verification of hybridizing American elm with other elms are rare.

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Growth and Yield

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American elm seldom grows in pure stands and there is no information on stand yields. On good sites in dense forest stands American elm may reach 30 to 38 m (98 to 125 ft) in height and 122 to 152 cm (48 to 60 in) in d.b.h., with a 15 m (49 ft) clear bole. On medium sites, heights of 24 m (80 ft) are common. On very wet soils or on the very dry soils of the Plains, however, the species is often only 12 to 18 m (40 to 60 ft) tall at maturity. In open-grown or sparse stands, the trees usually fork near the ground and form wide arching crowns. American elm is a long-lived species, often reaching 175 to 200 years, with some older than 300 years.

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Reaction to Competition

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American elm is classed as intermediate in shade tolerance among the eastern hardwoods. Usually it responds well to release, often growing more rapidly than its associates at advanced ages. Once it becomes dominant in a mixed hardwood stand, it is seldom overtaken by other species. It can persist in the understory of pioneer species such as eastern cottonwood, black willow, and quaking aspen (Populus tremuloides) but dies if suppressed by tolerant sugar maple or American beech (Fagus grandifolia).

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Rooting Habit

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The depth of rooting varies with soil texture and soil moisture. In heavy, wet soils the root system is widespread and within 0.9 to 1.2 m (3 to 4 ft) of the surface. On drier medium-textured soils, the roots usually penetrate 1.5 to 3.0 m (5 to 10 ft). In deep, relatively dry sands in the Dakotas, American elm may develop a taproot reaching 5.5 to 6.1 m (18 to 20 ft) down to the water table.

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Seed Production and Dissemination

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Seed production in American elm may begin as early as age 15 but is seldom abundant before age 40. When mature, American elm is a prolific seed producers Trees as old as 300 years have been reported to bear seeds. In closed stands, seed production is greatest in the exposed tops of dominant trees. The winged seeds are light and readily disseminated by the wind. Although most seeds fall within 91 in (300 ft) of the parent tree, some may be carried 0.4 kin (0.25 mi) or more. In river-bottom stands, the seeds may be waterborne for miles. Cleaned but not dewinged seeds average 156,000/kg (70,900/lb).

Adverse weather may reduce the seed crop. Spring frosts can injure and kill both flowers and fruit. Observations in Minnesota showed that while nearly ripe seeds were not injured by night temperatures of -3° C (27° F) for several successive nights, most were killed a week later when the temperature dropped to -7° C (19° F) and remained below freezing for 60 hours.

Mammals and birds also may reduce the seed crop. The flower buds, flowers, and fruit are eaten by gray squirrels. The seeds are also eaten by mice, squirrels, opossum, ruffed grouse, Northern bobwhite, and Hungarian partridge.

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Seedling Development

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Germination in American elm seed is epigeal. It usually germinates soon after it falls, although some seeds may remain dormant until the following spring. While germination may extend over a period of 60 days, most of the seeds germinate in 6 to 12 days. Germination is best with night temperatures at 20° C (68° F) and day temperatures of 30° C (86° F). However, germination is almost as good when daily temperatures range between 10° C (50° F) and 21° C (70° F). Seeds can germinate in darkness, but germination increases in light. Seeds also can lie on flooded ground for as long as 1 month with little adverse effect on germination, except possibly where siltation occurs in flooded bottoms.

American elm seedlings can become established on moist litter, moss, and decayed logs and stumps, but do best on mineral soil. Although they do grow in full sunlight, seedlings perform best with about one-third of full sunlight during the first year. After the first year or two, they grow best in full sunlight. Seedlings that develop in saturated soils are stunted and characterized by early yellowing and loss of the cotyledons, extremely short internodes, and small leaves.

American elm can withstand flooding in the dormant season but dies if the flooding is prolonged into the growing season. Compared with other bottomland species, American elm is intermediately tolerant to complete inundation. Some may be killed by early fall frosts, but those that survive soon are hardened by temperatures alternating between 0° C (32° F) and 10° C (50° F). A constant temperature of 0° C (32° F) for 5 days also hardens the seedlings enough to avoid frost killing (7).

Studies in Iowa and southeastern Michigan on wet lowland and upland mesic sites show that despite high mortality from Dutch elm disease, the next generation will be much like the last. Although American elm has been essentially eliminated from the overstory, it is a significant part of the understory and seedling layers. Some observations suggest that there will be a shift toward more intolerant species under the dead elms. American elm may be perpetuated for generations, even though the average life span of the trees is likely to be reduced. Where seeds are available, American elm is a prominent early invader of abandoned fields. On upland sites in the Midwest, fire, as a natural component of the environment, has kept American elm from invading the prairies (1,2,12,13).

In determining vegetational patterns and succession, allelopathy is apparently not as important for species coming in under American elm as it is for species coming in under sycamore, hackberry, northern red oak, and white oak. In a test in Missouri, there was lower productivity and higher percent soil moisture under all test species but American elm. This apparently was due to toxic leaf leachate present from the four test species, but not present in leachate from American elm (11).

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Soils and Topography

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American elm is most common on flats and bottom lands throughout its range but is not restricted to these sites. On the southern bottom-land region, it is found widely in first bottoms and terraces, especially on first bottom flats, but not in deep swamps. At higher elevations in the Appalachians, it is often limited to the vicinity of large streams and rarely appears at elevations above 610 in (2,000 ft). In West Virginia, however, it does appear in high coves at elevations of 760 in (2,500 ft). In the Lake and Central States, it is found on plains and morainal hills as well as on bottom lands and swamp margins. Along the northwestern edge of the range, it is usually restricted to valley bottoms along watercourses.

Although American elm is common on bottom-land soils, it is found on many of the great soil groups within its range. The soils include well-drained sands, organic bogs, undifferentiated silts, poorly drained clays, prairie loams, and many intermediate combinations.

American elm grows best on rich, well-drained loams. Soil moisture greatly influences its growth. Growth is poor in droughty sands and in soils where the summer water table is high. In Michigan, on loam and clay soils, growth is good when the summer water table drops 2.4 to 3.0 in (8 to 10 ft) below the surface, medium with summer water table at 1.2 to 2.4 in (4 to 8 ft), and poor when topsoil is wet throughout the year. On sandy soils underlain with clay, growth is medium to good where the summer water table is 0.6 m (2 ft) or more below the soil surface. Organic soils are usually poor sites, but those with a summer water table at least 0.6 m (2 ft) below the surface are classed as medium sites for American elm.

In the South, American elm is common on clay and silty-clay loams on first bottoms and terraces; growth is medium on wetter sites and good on well-drained flats in first bottoms (8). In the and western end of the range, it is usually confined to the silt or clay loams in river bottoms and terraces. In shelterbelt plantings on the uplands, however, survival is generally best on sandy soils where the moisture is more evenly distributed to greater depths than in fine-textured soils. American elm most commonly grows on soils of the orders Alfisols, Inceptisols, Mollisols, and Ultisols.

Soil acidity under stands of American elm varies from acid on some of the swamp margin sites in the Lake States to mildly alkaline on the prairie soils. A soil reaction considered suitable for this species ranges from pH 5.5 to 8.0.

Leaf litter of American elm decomposes more rapidly than that of sugar maple (Acer saccharum), shagbark hickory (Carya ovata), white oak (Quercus alba), and northern red oak (Q. rubra). Under Missouri conditions, the leaves crumble readily after 18 months on the ground. They have a relatively high content of potassium and also of calcium (1 to 2 percent). Because its litter decomposes rapidly and contains many desirable nutrients, American elm is considered a "soil-improving" species.

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Special Uses

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Before the advent of Dutch elm disease, American elm was prized for its use as a street tree. It was fast growing, hardy, tolerant to stress, and appreciated for its characteristic vaselike crown. Beautiful shaded streets in many cities attested to its popularity.

The wood of American elm is moderately heavy, hard, and stiff. It has interlocked grain and is difficult to split, which is an advantage for its use as hockey sticks and where bending is needed. It is used principally for furniture, hardwood dimension, flooring, construction and mining timbers, and sheet metal work. Some elm wood goes into veneer for making boxes, crates, and baskets, and a small quantity is used for pulp and paper manufacture.

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Vegetative Reproduction

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Small American elm trees produce vigorous stump sprouts. Although not documented, some observations suggest that replacement in dense, undisturbed bottom-land stands in Minnesota may be by root suckers of mature trees.

American elm can be propagated by softwood cuttings taken in June and treated with indolebutyric acid or by leaf bud cuttings. In a test, greenhouse-grown stock rooted easier than field-grown stock. Propagation by dormant root cuttings has not been effective.

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Brief Summary

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Ulmaceae -- Elm family

Calvin F. Bey

American elm (Ulmus americana), also known as white elm, water elm, soft elm, or Florida elm, is most notable for its susceptibility to the wilt fungus, Ceratocystis ulmi. Commonly called Dutch elm disease, this wilt has had a tragic impact on American elms. Scores of dead elms in the forests, shelterbelts, and urban areas are testimony to the seriousness of the disease. Because of it, American elms now comprise a smaller percentage of the large diameter trees in mixed forest stands than formerly. Nevertheless, the previously developed silvical concepts remain basically sound.

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Distribution

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American elm is found throughout Eastern North America. Its range is from Cape Breton Island, Nova Scotia, west to central Ontario, southern Manitoba, and southeastern Saskatchewan; south to extreme eastern Montana, northeastern Wyoming, western Nebraska, Kansas, and Oklahoma into central Texas; east to central Florida; and north along the entire east coast.


The native range of American elm.


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Ulmus americana

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Ulmus americana, generally known as the American elm or, less commonly, as the white elm or water elm,[a] is a species of elm native to eastern North America, naturally occurring from Nova Scotia west to Alberta and Montana, and south to Florida and central Texas. The American elm is an extremely hardy tree that can withstand winter temperatures as low as −42 °C (−44 °F). Trees in areas unaffected by Dutch elm disease (DED) can live for several hundred years. A prime example of the species was the Sauble Elm,[3] which grew beside the banks of the Sauble River in Ontario, Canada, to a height of 43 m (140 ft), with a d.b.h of 196 cm (6.43 ft) before succumbing to DED; when it was felled in 1968, a tree-ring count established that it had germinated in 1701.

For over 80 years, U. americana had been identified as a tetraploid, i.e. having double the usual number of chromosomes, making it unique within the genus. However, a study published in 2011 by the Agricultural Research Service of the USDA revealed that about 20% of wild American elms are diploid and may even constitute another species. Moreover, several triploid trees known only in cultivation, such as 'Jefferson', are possessed of a high degree of resistance to DED, which ravaged American elms in the 20th century. This suggests that the diploid parent trees, which have markedly smaller cells than the tetraploid, may too be highly resistant to the disease.[4][5]

Classification

Ulmus americana was first described and named by Carl Linnaeus in his Species Plantarum, published in 1753. No subspecies or varieties are currently recognized within the species.

Description

The American elm is a deciduous monoecious tree which, before the introduction of DED, commonly grew to more than 100 feet (30 m) tall with a trunk whose diameter at breast height was more than 4 feet (1.2 m), supporting a high, spreading umbrella-like canopy. The leaves are alternate, 7–20 cm long, with double-serrate margins and an oblique base. The perfect flowers are small, purple-brown and, being wind-pollinated, apetalous. The flowers are also protogynous, the female parts maturing before the male, thus reducing, but not eliminating, self-fertilization,[6] and emerge in early spring before the leaves. The fruit is a flat samara 2 cm long by 1.5 cm broad, with a circular papery wing surrounding the single 4–5 mm seed. As in the closely related European White Elm Ulmus laevis, the flowers and seeds are borne on 1–3 cm long stems. American Elm is wholly insensitive to daylight length (photoperiod), and will continue to grow well into autumn until injured by frost.[7] Ploidy is 2n = 56, or more rarely, 2n = 28.[8]

Ecology

The American elm occurs naturally in an assortment of habitats, most notably rich bottomlands, floodplains, stream banks, and swampy ground, although it also often thrives on hillsides, uplands and other well-drained soils.[9] On more elevated terrain, as in the Appalachian Mountains, it is most often found along rivers.[10] The species' wind-dispersed seeds enable it to spread rapidly as suitable areas of habitat become available.[9] American elm fruits in late spring (which can be as early as February and as late as June depending on the climate), the seeds usually germinating immediately, with no cold stratification needed (occasionally some might remain dormant until the following year). The species attains its greatest growth potential in the Northeastern US, while elms in the Deep South and Texas grow much smaller and have shorter lifespans, although conversely their survival rate in the latter regions is higher owing to the climate being less favorable to the spread of DED.

In the United States, the American elm is a principal member of four major forest cover types: black ash-American elm-red maple; silver maple-American elm; sugarberry-American elm-green ash; and sycamore-sweetgum-American elm, with the first two of these types also occurring in Canada.[11] A sugar maple-ironwood-American elm cover type occurs on some hilltops near Témiscaming, Quebec.[12]

The leaves of the American elm serve as food for the larvae of a number of species of Lepidoptera (see List of Lepidoptera that feed on elms). These include such butterflies as the Eastern Comma (Polygonia comma), Question Mark (Polygonia interrogationis), Mourning Cloak (Nymphalis antiopa), Painted Lady (Vanessa cardui) and Red-spotted Purple (Limenitis arthemis astyanax), as well as such moths as the Columbian Silkmoth (Hyalophora columbia) and the Banded Tussock Moth (Pale Tiger Moth) (Halysidota tessellaris).[13]

Pests and diseases

The American elm is highly susceptible to DED and elm yellows. In North America, there are three species of elm bark beetles: one native, Hylurgopinus rufipes ("native elm bark beetle"); and two invasive, Scolytus multistriatus ("smaller European elm bark beetle") and Scolytus schevyrewi ("banded elm bark beetle"). Although intensive feeding by elm bark beetles can kill weakened trees,[14] their main impact is as vectors of DED.

American elm is also moderately preferred for feeding and reproduction by the adult elm leaf beetle Xanthogaleruca luteola[15] and highly preferred for feeding by the Japanese beetle Popillia japonica[16] in the United States.

U. americana is also the most susceptible of all the elms to verticillium wilt,[17] whose external symptoms closely mimic those of DED. However, the condition is far less serious, and afflicted trees should recover the following year.

Dutch elm disease

Dutch elm disease (DED) is a fungal disease that has ravaged the American elm, causing catastrophic die-offs in cities across the range. It has been estimated that only approximately 1 in 100,000 American elm trees is DED-tolerant, most known survivors simply having escaped exposure to the disease.[18] However, in some areas still not infested by DED, the American elm continues to thrive, notably in Florida, Alberta and British Columbia. There is a notable grove of old American elm trees in Manhattan's Central Park. The trees there were apparently spared because of the grove's isolation in such an intensely urban setting.

The American elm is particularly susceptible to disease because the period of infection often coincides with the period, approximately 30 days, of rapid terminal growth when new springwood vessels are fully functional. Spores introduced outside of this period remain largely static within the xylem and are thus relatively ineffective.[19]

The American elm's biology in some ways has helped to spare it from obliteration by DED, in contrast to what happened to the American chestnut with the chestnut blight. The elm's seeds are largely wind-dispersed, and the tree grows quickly and begins bearing seeds at a young age. It grows well along roads or railroad tracks, and in abandoned lots and other disturbed areas, where it is highly tolerant of most stress factors. Elms have been able to survive and to reproduce in areas where the disease had eliminated old trees, although most of these young elms eventually succumb to the disease at a relatively young age. There is some reason to hope that these elms will preserve the genetic diversity of the original population, and that they eventually will hybridize with DED-resistant varieties that have been developed or that occur naturally. After 20 years of research, American scientists first developed DED-resistant strains of elms in the late 1990s.[18]

Elms in forest and other natural areas have been less affected by DED than trees in urban environments due to lower environmental stress from pollution and soil compaction and due to occurring in smaller, more isolated populations.

Fungicidal injections can be administered to valuable American elms, to prevent infection. Such injections generally are effective as a preventive measure for up to three years when performed before any symptoms have appeared, but may be ineffective once the disease is evident.

Cultivation

In the 19th and early 20th century, American elm was a common street and park tree owing to its tolerance of urban conditions, rapid growth, and graceful form. This however led to extreme overplanting of the species, especially to form living archways over streets, which ultimately produced an unhealthy monoculture of elms that had no resistance to disease and pests. Elms do not naturally form pure stands and trees used in landscaping were grown from a handful of cultivars, causing extremely low genetic diversity.[20] These trees' rapid growth and longevity, leading to great size within decades, made them popular before the advent of DED.[9] Ohio botanist William B. Werthner, discussing the contrast between open-grown and forest-grown American elms, noted that:

"In the open, with an abundance of air and light, the main trunk divides into several leading branches which leave the trunk at a sharp angle and continue to grow upward, gradually diverging, dividing and subdividing into long, flexible branchlets whose ends, at last, float lightly in the air, giving the tree a round, somewhat flattened top of beautifully regular proportions and characteristically fine twiggery."[9]

It is this distinctive growth form that is so valued in the open-grown American elms of street plantings, lawns, and parks; along most narrower streets, elms planted on opposite sides arch and blend together into a leafy canopy over the pavement. However, elms can assume many different sizes and forms depending on the location and climate zone. In 1926 the Klehm Nurseries of Arlington Heights, Illinois, wrote: "American Elms grown in the regular way from seedlings show extreme variability, growing up into trees of all shapes, some of them being very slow in growth while others are moderately rapid in development. The shapes run all the way from the true open excurrent growth to globular, or flat-topped, or pendant. As regards foliage, the leaves are from small to medium large, some shedding early and others late. This condition makes it difficult for the landscape architect to choose just the right trees to obtain the effect desired."[21] The classic vase-shaped elm was mainly the result of selective breeding of a few cultivars and is much less likely to occur in the wild.[22]

American elms have been planted in North America beyond its natural range as far north as central Alberta. It also survives low desert heat at Phoenix, Arizona.

Introductions across the Atlantic rarely prospered, even before the outbreak of DED. Introduced to the UK by James Gordon[1] in 1752, the American elm was noted to be far more susceptible to insect foliage damage than native elms.[23] The tree was propagated and marketed in the UK by the Hillier & Sons nursery, Winchester, Hampshire from 1945, with 450 sold in the period 1962 to 1977 when production ceased with the advent of the more virulent form of Dutch elm disease.[24][25] Introduced to Australasia, the tree was listed by Australian nurseries in the early 20th century. It is known to have been planted along the Avenue of Honour at Ballarat, Victoria and the Avenue of Honour in Bacchus Marsh, Victoria. In addition, a heritage-listed planting of American elms can be found along Grant Crescent in Griffith, Australian Capital Territory.[26] American Elms are only rarely found in New Zealand.[27]

The American elm in literature

Mary Eleanor Wilkins Freeman, in her 1903 book of short stories, Six Trees, wrote of the American elm:

There was not in the whole countryside another tree which could compare with him. He was matchless. Never a stranger passed the elm but stopped, and stared, and said or thought something about it. Even dull rustics looked, and had a momentary lapse from vacuity.[28]

Cultivars

Numerous cultivars have been raised, originally for their aesthetic merit but more recently for their resistance to Dutch elm disease[29] The total number of named cultivars is circa 45, at least 18 of which have probably been lost to cultivation as a consequence of DED or other factors:

and others.[30]

The disease-resistant selections made available to commerce to date include 'Valley Forge', 'New Harmony', 'Princeton', 'Jefferson', 'Lewis & Clark', 'Miller Park', 'St. Croix', 'Endurance', and a set of six different clones collectively known as 'American Liberty'.[31] The United States National Arboretum released 'Valley Forge' and 'New Harmony' in late 1995, after screening tests performed in 1992–1993 showed both had unusually high levels of resistance to DED. 'Valley Forge' performed especially well in these tests.[32]

'Princeton' has been in occasional cultivation since the 1920s. 'Princeton' gained renewed attention after its performance in the 1992–1993 screening tests showed that it also had a high degree of disease resistance. A later test performed in 2002–2003 confirmed the disease resistance of 'Princeton', 'Valley Forge' and 'New Harmony', as well as that of 'Jefferson'. Thus far, plantings of these four varieties generally appear to be successful.

In 2005, approximately 90 'Princeton' elms were planted along Pennsylvania Avenue in front of the White House in Washington, D.C. The trees, whose maintenance the National Park Service (NPS) manages, remain healthy and are thriving.[33] However, it has been noted that U. americana cultivars are not recommended for more than singular plantings as they have unresolved DED and elm yellows concerns.[34]

It has also been noted that monoculture plantings of U. americana cultivars, such as those along Pennsylvania Avenue, have disproportionate vulnerabilities to disease.[34] Further, long-term studies of 'Princeton' in Europe and the United States have suggested that the cultivar's resistance to DED may be limited (see Pests and diseases of 'Princeton').

The National Elm Trial evaluated 19 elm cultivars commercially available in the United States in scientific plantings throughout the nation to assess and compare the strengths and weaknesses of each. The trial, which started in 2005, lasted for ten years. Based on the trial's final ratings, the preferred cultivars of U. americana are 'New Harmony' and 'Princeton'.[35]

'Jefferson' was released to wholesale nurseries in 2004 and is becoming increasingly available for planting. However, 'Jefferson' has not been widely tested beyond Washington, D.C. The National Elm Trial provided no data on ‘Jefferson’ because an error in tree identification had occurred earlier in the nursery trade.[36] The error may still be causing nurseries to sell 'Princeton' elms that are mislabeled as 'Jefferson', although one can distinguish between the two cultivars as the trees mature.[34][37]

In 2007, the 'Elm Recovery Project'[38] from the University of Guelph in Ontario, Canada, reported that cuttings from healthy surviving old elms surveyed across Ontario had been grown to produce a bank of resistant trees, isolated for selective breeding of highly resistant cultivars.[39]

In 1993, Mariam B. Sticklen and James L. Sherald reported the results of NPS-funded experiments conducted at Michigan State University in East Lansing that were designed to apply genetic engineering techniques to the development of DED-resistant strains of American elm trees.[40] In 2007, AE Newhouse and F Schrodt of the State University of New York College of Environmental Science and Forestry in Syracuse reported that young transgenic American elm trees had shown reduced DED symptoms and normal mycorrhizal colonization.[41]

Hybrids and hybrid cultivars

Thousands of attempts to cross the American elm with the Siberian elm U. pumila failed.[42] Attempts at the Arnold Arboretum using ten other American, European and Asiatic species also ended in failure, attributed to the differences in ploidy and operational dichogamy,[6] although the ploidy factor has been discounted by other authorities.[43]

Success was eventually achieved with the autumn-flowering Chinese elm Ulmus parvifolia by the late Prof. Eugene Smalley towards the end of his career at the University of Wisconsin–Madison after he overcame the problem of keeping Chinese elm pollen alive until spring.[44] Only one of the hybrid clones was commercially released, as 'Rebella' in 2011 by the German nursery Eisele GmbH; the clone is not available in the United States.

Other artificial hybridizations with American elm are rare, and now regarded with suspicion. Two such alleged successes by the nursery trade were 'Hamburg', and 'Kansas Hybrid', both with Siberian elm Ulmus pumila. However, given the repeated failure with the two species by research institutions, it is now believed that the "American elm" in question was more likely to have been the red elm, Ulmus rubra.[45]

Other uses

Wood

A wooden hand plane made of American elm

The American elm's wood is coarse, hard, and tough, with interlacing, contorted fibers that make it difficult to split or chop, and cause it to warp after sawing.[9] Accordingly, the wood originally had few uses, save for making hubs for wagon wheels.[9] Later, with the advent of mechanical sawing, American elm wood was used for barrel staves, trunk-slats, and hoop-poles, and subsequently became fundamental to the manufacture of wooden automobile bodies, with the intricate fibers holding screws unusually well.[9]

Pioneer and traditional uses

Young twigs and branchlets of the American elm have tough, fibrous bark that has been used as a tying and binding material, even for rope swings for children, and also for making whips.[9]

Notable trees

A number of mostly small to medium-sized American elms now survive in woodlands, suburban areas, and occasionally cities, where the survivors have often been relatively isolated from other elms and thus spared a severe exposure to the fungus. For example, in Central Park and Tompkins Square Park in New York City, stands of several large elms originally planted by Frederick Law Olmsted survive because of their isolation from neighboring areas in New York where there had been heavy mortality.[46] The Olmsted-designed park system in Buffalo, NY[47] did not fare as well.

A row of mature American elms lines Central Park along the entire length of Fifth Avenue from 59th to 110th Streets.[48] In Akron, Ohio there is a very old elm tree that has not been infected. In historical areas of Philadelphia, Pennsylvania, there are also a few mature American elms still standing — notably in Independence Square and the Quadrangle at the University of Pennsylvania, and also at the nearby campuses of Haverford College, Swarthmore College, and Pennsylvania State University, believed to be the largest remaining stand in the country.[49]

There are several large American Elm trees in western Massachusetts. A large specimen, which stands on Summer Street in the Berkshire County town of Lanesborough, Massachusetts, has been kept alive by antifungal treatments. Rutgers University has preserved 55 mature elms on and in the vicinity of Voorhees Mall on the College Avenue Campus in New Brunswick, New Jersey in addition to seven disease-resistant trees that have been planted in this area of the campus in recent years.[50]

The largest surviving urban forest of American elms in North America is believed to be in the city of Winnipeg, Manitoba, Canada, where close to 200,000 elms remain. The city of Winnipeg spends $3M annually to aggressively combat the disease utilizing Dursban Turf[51] and the Dutch Trig vaccine,[52] losing 1500–4000 trees per year.

Governmental agencies, educational institutions or other organizations in most of the states that are within the United States maintain lists of champion or big trees that describe the locations and characteristics of those states' largest American elm trees (see List of state champion American elm trees). The current United States national champion American elm tree is located in Iberville Parish, Louisiana. When measured in 2010, the tree had a trunk circumference of 324 inches (820 cm), a height of 111 feet (34 m) and an average crown spread of 79 feet (24 m).[53]

The current Tree Register of the British Isles (TROBI) champion grows in Avondale Forest near Rathdrum, County Wicklow, Ireland. The tree had a height of 22.5 metres (74 ft) and a diameter at breast height of 98 centimetres (39 in) (circumference of 308 centimetres (121 in)) when measured in 2000.[54] The tree replaced on the Register a larger champion located in Woodvale Cemetery in Sussex, England, which in 1988 had a height of 27 metres (89 ft) and a diameter of 115 centimetres (45 in) (circumference of 361 centimetres (142 in)).[55]

Other large or otherwise significant American elm trees have included:

Treaty Elm

William Penn and Indians with treaty under a large elm in 1683, as shown in a painting by Benjamin West

The Treaty Elm, Philadelphia, Pennsylvania. In what is now Penn Treaty Park, the founder of Pennsylvania, William Penn, is said to have entered into a treaty of peace in 1683 with the native Lenape Turtle Clan under a picturesque elm tree immortalized in a painting by Benjamin West. West made the tree, already a local landmark, famous by incorporating it into his painting after hearing legends (of unknown veracity) about the tree being the location of the treaty. No documentary evidence exists of any treaty Penn signed beneath a particular tree. On March 6, 1810 a great storm blew the tree down. Measurements taken at the time showed it to have a circumference of 24 feet (7.3 m), and its age was estimated to be 280 years. Wood from the tree was made into furniture, canes, walking sticks and various trinkets that Philadelphians kept as relics.[56]

Washington Elm (Massachusetts)

The Washington Elm, Cambridge, Massachusetts. George Washington is said to have taken command of the American Continental Army under the Washington Elm in Cambridge on July 3, 1775. The tree survived until the 1920s and "was thought to be a survivor of the primeval forest". In 1872, a large branch fell from it and was used to construct a pulpit for a nearby church.[57] The tree, an American white elm, became a celebrated attraction, with its own plaque, a fence constructed around it and a road moved in order to help preserve it.[58] The tree was cut down (or fell—sources differ) in October 1920 after an expert determined it was dead.

The city of Cambridge had plans for it to be "carefully cut up and a piece sent to each state of the country and to the District of Columbia and Alaska," according to The Harvard Crimson.[59] As late as the early 1930s, garden shops advertised that they had cuttings of the tree for sale, although the accuracy of the claims has been doubted. A Harvard "professor of plant anatomy" examined the tree rings days after the tree was felled and pronounced it between 204 and 210 years old, making it at most 62 years old when Washington took command of the troops at Cambridge. The tree would have been a little more than two feet in diameter (at 30 inches above ground) in 1773.[60]

In 1896, an alumnus of the University of Washington, obtained a rooted cutting of the Cambridge tree and sent it to Professor Edmund Meany at the university. The cutting was planted, cuttings were then taken from it, including one planted on February 18, 1932, the 200th anniversary of the birth of George Washington, for whom Washington state is named. That tree remains on the campus of the Washington State Capitol. Just to the west of the tree is a small elm from a cutting made in 1979.[58]

Washington Elm (District of Columbia)

George Washington's Elm, Washington, D.C. George Washington supposedly had a favorite spot under an elm tree near the United States Capitol Building from which he would watch construction of the building. The elm stood near the Senate wing of the Capitol building until 1948.[57]

Logan Elm

The Logan Elm that stood near Circleville, Ohio, was one of the largest American elms in the world. The 65-foot-tall (20 m) tree had a trunk circumference of 24 feet (7.3 m) and a crown spread of 180 feet (55 m).[61] Weakened by DED, the tree died in 1964 from storm damage.[61] The Logan Elm State Memorial commemorates the site and preserves various associated markers and monuments.[61] According to tradition, Chief Logan of the Mingo tribe delivered a passionate speech at a peace-treaty meeting under this elm in 1774.[61][62]

"Herbie"

An April 21, 2008, picture of Herbie

Another notable American elm, named Herbie, was the tallest American elm in New England until it was cut down on January 19, 2010, after it succumbed to DED. Herbie was 110 feet (34 m) tall at its peak and had a circumference of 20.3 feet (6.2 m), or a diameter of approximately 6.5 feet (2.0 m). The tree stood in Yarmouth, Maine, where it was cared for by the town's tree warden, Frank Knight.[63]

When cut down, Herbie was 217 years old. Herbie's wood is of interest to dendroclimatologists, who will use cross-sections of the trunk to help answer questions about climate during the tree's lifetime.[63]

The Glencorradale Elm

The Glencorradale Elm on Prince Edward Island, Canada, is a surviving wild elm believed to be several hundred years old.[64]

Survivor Tree

The Survivor Tree at the Oklahoma City National Memorial (2004)

An American elm located in a parking lot directly across the street from the Alfred P. Murrah Federal Building in Oklahoma City survived the Oklahoma City bombing on April 19, 1995, that killed 168 people and destroyed the Murrah building. Damaged in the blast, with fragments lodged in its trunk and branches, it was nearly cut down in efforts to recover evidence. However, nearly a year later the tree began to bloom. Then known as the Survivor Tree, it became an important part of the Oklahoma City National Memorial, and is featured prominently on the official logo of the memorial.[65]

Parliament Hill Elm

The Parliament Hill Elm was planted in Ottawa, Canada, in the late 1910s or early 1920s when Centre Block was rebuilt following the Great fire of 1916. The tree grew for approximately a century next to a statue of John A. Macdonald and was one of the few in the region to survive the spread of DED in the 1970s and 1980s.[66] Despite protests from Ottawa area environmentalists and resistance from Opposition Members of Parliament the tree was removed in April 2019 to make way for new Centre Block renovations.[67]

Photo gallery

Landscaped parks

Central Park

American elms along The Mall and Literary Walk, Central Park (2013)

New York City's Central Park is home to approximately 1,200 American elms. The oldest of these elms were planted during the 1860s by Frederick Law Olmsted, making them among the oldest stands of American elms in the world. The trees are particularly noteworthy along the Mall and Literary Walk, where four lines of American elms stretch over the walkway forming a cathedral-like covering. A part of New York City's urban ecology, the elms improve air and water quality, reduce erosion and flooding, and decrease air temperatures during warm days.[71]

While the stand is still vulnerable to DED, in the 1980s the Central Park Conservancy undertook aggressive countermeasures such as heavy pruning and removal of extensively diseased trees. These efforts have largely been successful in saving the majority of the trees, although several are still lost each year. Younger American elms that have been planted in Central Park since the outbreak are of the DED-resistant 'Princeton' and 'Valley Forge' cultivars.[72]

National Mall

Rows of American elm trees line a path south of the Lincoln Memorial Reflecting Pool on the National Mall in Washington, D.C. (November 11, 2006).

Several rows of American elm trees that the National Park Service first planted during the 1930s line much of the 1.9 miles (3.0 km) length of the National Mall in Washington, D.C. DED first appeared on the trees during the 1950s and reached a peak in the 1970s. The NPS used a number of methods to control the epidemic, including sanitation, pruning, injecting trees with fungicide and replanting with DED-resistant cultivars. The NPS combated the disease's local insect vector, the smaller European elm bark beetle (Scolytus multistriatus), by trapping and by spraying with insecticides. As a result, the population of American elms planted on the Mall and its surrounding areas has remained intact for more than 80 years.[73]

In art and photography

The nobility and arching grace of the American Elm in its heyday, on farms, in villages, in towns and on campuses, were celebrated in the books of photographs of Wallace Nutting (Massachusetts Beautiful, N.Y. 1923, and other volumes in the series) and of Samuel Chamberlain (The New England Image, New York, 1962). Frederick Childe Hassam is notable among painters who have depicted American Elm.

Accessions

North America
Europe
Australasia

See also

Notes

  1. ^ The name "water elm" is also used for Planera aquatica, another species in the Ulmaceae.

References

  1. ^ Stritch, L., Rivers, M.C., Barstow, M. (2020) [amended version of 2019 assessment]. "Ulmus americana". IUCN Red List of Threatened Species. 2018: e.T61966619A180057317. doi:10.2305/IUCN.UK.2020-3.RLTS.T61966619A180057317.en.{{cite journal}}: CS1 maint: multiple names: authors list (link)|volume= / |date= mismatch
  2. ^ "Ulmus americana". NatureServe Explorer. NatureServe. Archived from the original on September 29, 2007. Retrieved July 6, 2007.
  3. ^ (1) "The Lord of the Elms". Spare The Axe, Save The Tree. flyingsquirrels.com. Archived from the original on July 11, 2017.
    (2) "Of Elms and Orioles". Emmitsburg News-Journal: The New Forest Society. Archived from the original on December 17, 2014. Retrieved December 15, 2014.
  4. ^ Whittemore, A. & Olsen, R. (2011). Ulmus americana (Ulmaceae) is a polyploidy complex. American Journal of Botany 98(4): 754–760. 2011. Botanical Society of America.
  5. ^ Kaplan, K. (March 30, 2011). "Hidden elm population may hold genes to combat Dutch elm disease". ARS News. United States Department of Agriculture: Agricultural Research Service. Archived from the original on April 2, 2015.
  6. ^ a b Hans, A. S. (1981). "Compatibility and Crossability Studies in Ulmus". Silvae Genetica. 30: 4–5.
  7. ^ Downs, R. J.; Borthwick, H. A. (1956). "Effects of Photoperiod on Growth of Trees". Botanical Gazette. 117 (4): 310–326. doi:10.1086/335918. S2CID 83948676.
  8. ^ Whittemore, A. T.; Olsen, R. T. (2011). "Ulmus americana (Ulmaceae) is a Polyploid Complex". American Journal of Botany. 98 (4): 754–760. doi:10.3732/ajb.1000372. PMID 21613171. Archived from the original on October 28, 2020. Retrieved April 29, 2018.
  9. ^ a b c d e f g h Werthner, William B. (1935). Some American Trees: An Intimate Study of Native Ohio Trees. New York: The Macmillan Company. pp. xviii, 398.
  10. ^ Strausbaugh, P.D.; Core, E.L. (1978). Flora of West Virginia (2 ed.). Morgantown, WV: Seneca Books, Inc. pp. xl, 1079.
  11. ^ Bey, Calvin F. (1990). "Ulmus americana". In Burns, Russell M.; Honkala, Barbara H. (eds.). Hardwoods. Silvics of North America. Washington, D.C.: United States Forest Service (USFS), United States Department of Agriculture (USDA). Vol. 2. Retrieved December 14, 2014 – via Southern Research Station.
  12. ^ Brown, Jean-Louis (1981). Les forêts du Témiscamingue, Québec: écologie et photo-interprétation (in French). Quebec City, Canada: Laboratoire d'écologie forestière, Université Laval, Québec. ISBN 978-2-9201-0404-4.
  13. ^ (1) "Eastern Comma: Polygonia comma (Harris, 1842)". Butterflies and Moths of North America. 2019. Archived from the original on November 1, 2019. Retrieved December 13, 2019 – via Metalmark Web and Data.
    (2) "Question Mark: Polygonia interrogationis (Fabricius, 1798)". Butterflies and Moths of North America. 2019. Archived from the original on November 1, 2019. Retrieved December 13, 2019 – via Metalmark Web and Data.
    (3) "Mourning Cloak: Nymphalis antiopa (Linnaeus, 1758)". Butterflies and Moths of North America. 2019. Archived from the original on November 1, 2019. Retrieved December 13, 2019 – via Metalmark Web and Data.
    (4) "Ulmus americana: American elm". Florida Native Plant Society. 2013. Archived from the original on March 1, 2018. Retrieved December 13, 2019.
    (5) Mogren, Chrissy. "Louisiana Native Pollinator Trees" (PDF). Baton Rouge, Louisiana: Louisiana State University Ag Center Botannic Gardens. Archived (PDF) from the original on December 13, 2019. Retrieved December 13, 2019.
    (6) "Ulmus americana". North Carolina Extension Gardener Plant Toolbox. Raleigh, North Carolina: North Carolina State University. Archived from the original on December 13, 2019. Retrieved December 13, 2019.
    (7) "Ulmus americana". Plant Database. Austin, Texas: University of Texas at Austin: Lady Bird Johnson Wildflower Center. Archived from the original on December 13, 2019. Retrieved December 13, 2019.
  14. ^ Negrón JF, Witcoski JJ, Cain JJ, LaBonte JR, Duerr DA II, McElwe SJ, Lee JC, Seybold SJ (2005). The banded elm bark beetle: a new threat to elms in North America. American Entomologist, 51:84-94
  15. ^ Miller, F.; Ware, G. (2001). "Resistance of Temperate Chinese Elms (Ulmuss spp.) to Feeding of the Adult Elm Leaf Beetle (Coleoptera: Chrysomelidae)". Journal of Economic Entomology. 94 (1): 162–166. doi:10.1603/0022-0493-94.1.162. PMID 11233108. S2CID 42980569.
  16. ^ Miller, F.; Ware, G.; Jackson, J. (2001). "Preference of Temperate Chinese Elms (Ulmuss spp.) for the Feeding of the Japanese Beetle (Coleoptera: Scarabaeidae)". Journal of Economic Entomology. 94 (2): 445–448. doi:10.1603/0022-0493-94.2.445. PMID 11332837. S2CID 7520439.
  17. ^ Pegg, G. F.; Brady, B. L. (2002). Verticillium Wilts. Wallingford, Oxfordshire, UK: CABI Publishing. ISBN 0-85199-529-2.
  18. ^ a b "New American Elms Restore Stately Trees". Agricultural Research Service, United States Department of Agriculture. July 1996. Archived from the original on December 19, 2014. Retrieved December 18, 2014.
  19. ^ Smalley, E. G. (1963). "Seasonal Fluctuations in Susceptibility of Young Elm Seedlings to Dutch Elm Disease". Phytopathology. 53 (7): 846–853.
  20. ^ Stennes, Mark (2003). "Good News for the American Elm". Shade Tree Advocate. 5 (4): 6.
  21. ^ 'Three novelties for 1926: Ulmus americana 'Molinii', Ulmus americana 'Urnii', Populus alba 'Richardii' ' : bulletin of Klehms' Nurseries, Illinois
  22. ^ Laney, C. C., 'The types of the American elm', trees.umn.edu
  23. ^ Elwes, Henry John; Henry, Augustine (1913). The Trees of Great Britain & Ireland. Vol. 7. pp. 1855–1859.
  24. ^ Hillier & Sons (1977). Catalogue of Trees & Shrubs. Hillier, Ampfield, UK.
  25. ^ Hillier & Sons Sales inventory 1962 to 1977 (unpublished).
  26. ^ ACT Government (February 2, 2012). "ACT Tree Register, Grant Crescent" (PDF). ACT Tree Register, Grant Crescent. ACT Government. Archived (PDF) from the original on March 20, 2016. Retrieved July 7, 2016.
  27. ^ Wilcox, Mike; Inglis, Chris (2003). "Auckland's elms" (PDF). Auckland Botanical Society Journal. Auckland Botanical Society. 58 (1): 38–45. Archived from the original (PDF) on January 6, 2015. Retrieved February 7, 2017.
  28. ^ Freeman, Mary E. Wilkins (1903). "The Elm—Tree". Six Trees. New York and London: Harper & Brothers. p. 4. Retrieved February 8, 2021 – via Internet Archive.
  29. ^ Townsend, A. M.; Bentz, S. E.; Douglass, L. W. (March 2005). "Evaluation of 19 American Elm Clones for Tolerance to Dutch Elm Disease" (PDF). Journal of Environmental Horticulture. 23: 21–24. doi:10.24266/0738-2898-23.1.21. Archived (PDF) from the original on May 11, 2005. Retrieved November 7, 2006.
  30. ^ "Elm cultivars". Lisle, Illinois: Morton Arboretum. 2021. Archived from the original on May 14, 2020. Retrieved February 8, 2020. Accolade® (Ulmus davidiana var. japonica 'Morton') .... Commendation™ (Ulmus 'Morton Stalwart') .... Danada Charm™ (Ulmus 'Morton Red Tip') .... Emerald Sunshine® (Ulmus davidiana var. japonica 'JFS-Bieberich') .... Frontier (Ulmus 'Frontier') .... Homestead (Ulmus 'Homestead'): .... Jefferson (Ulmus americana 'Jefferson') .... New Harmony (Ulmus americana 'New Harmony') .... New Horizon (Ulmus 'New Horizon') .... Patriot (Ulmus 'Patriot') .... Pioneer (Ulmus 'Pioneer') .... Prairie Expedition® (Ulmus americana 'Lewis & Clark'): .... Princeton (Ulmus americana 'Princeton') .... Prospector (Ulmus davidiana var. japonica 'Prospector') .... Regal (Ulmus 'Regal') .... Triumph™ (Ulmus 'Morton Glossy') .... Valley Forge (Ulmus americana 'Valley Forge') .... Vanguard™ (Ulmus 'Morton Plainsman').
  31. ^ Costello, L. R. (March 2004). "A 10-year Evaluation of the Performance of Four Elm Cultivars in California, U. S." Journal of Arboriculture. Archived from the original on October 6, 2008.
  32. ^ (1) Carley, Bruce (January 2, 2017). "The Solution". Saving the American Elm. Archived from the original on January 25, 2021. Retrieved February 8, 2020.
    (2) Townsend, A.M.; Bentz, S.E.; Johnson, G.R. (1995). "Variation in Response of Selected American Elm Clones to Ophiostoma ulmi". Journal of Environmental Horticulture. 13 (3): 126–128. doi:10.24266/0738-2898-13.3.126. ISSN 0738-2898. LCCN 83643944. OCLC 8656790939.
  33. ^ (1) "Elm, Princeton - Ulmus americana 'Princeton'". South Chatsworth, Georgia: Native Forest Nursery. 2016. Archived from the original on May 1, 2019. Retrieved April 28, 2019.
    (2) Sanders, Jessica R.; Woodworth Jr., James W. (November 25, 2013). "Proactive, Not Reactive: Evolving Elm Management in the Nation's Capital". Cities and the Environment (CATE). 6 (1, article 8). Archived from the original on May 1, 2019. Retrieved April 28, 2019 – via Digital Commons @ LMU and LLS.
    (3) Sherald, James L (December 2009). Elms for the Monumental Core: History and Management Plan (PDF). Washington, D.C.: Center for Urban Ecology, National Capital Region, National Park Service. p. 39. Natural Resource Report NPS/NCR/NRR--2009/001. Archived (PDF) from the original on November 29, 2010. Retrieved October 14, 2010.
  34. ^ a b c Zetterstrom, Tom (2017). Pinchot, Cornelia C.; Knight, Kathleen S.; Haugen, Linda M.; Flower, Charles E.; Slavicek, James M. (eds.). "Report From the Street" (PDF). Proceedings of the American Elm Restoration Workshop 2016; 2016 October 25–27; Lewis Center, OH. Newtown Square, PA. United States Department of Agriculture, United States Forest Service, Northern Research Station: 119–121. doi:10.2737/NRS-GTR-P-174. OCLC 1231892730. Gen. Tech. Rep. NRS-P-174. Archived (PDF) from the original on May 1, 2019. Retrieved February 7, 2021. Because of unresolved DED and elm yellows concerns, American elm cultivars are not recommended for more than singular plantings, according to Elm Watch and Bruce Fraedrich of Bartlett Tree Research Lab (Charlotte, NC). .... Monoculture plantings, such as alongside Pennsylvania Avenue in Washington, D.C., have disproportionate vulnerabilities to disease, and because of a poor understanding of pruning goals, uniformity of streetscape design may likely become disrupted over time along that Inauguration Day parade route due to expected failures of major structural leaders.
  35. ^ (1) "National Elm Trial". Bioagricultural Sciences & Pest Management. Fort Collins, Colorado: Colorado State University College of Agricultural Sciences: Department of Agricultural Biology. 2018. Archived from the original on March 30, 2018. Retrieved February 8, 2021.
    (2) Griffin, Jason J.; Jacobi, E., William R.; McPherson, Gregory; Sadof, Clifford S.; et al. (2017). "Ten-Year Performance of the United States National Elm Trial" (PDF). Arboriculture & Urban Forestry. International Society of Arboriculture. 43 (3): 107–120. doi:10.17660/ActaHortic.2018.1191.5. ISSN 0567-7572. OCLC 7347020445. Retrieved February 7, 2021. Based on the ratings, the preferred cultivars of American elm were 'New Harmony' and 'Princeton', and the preferred cultivars of Asian elm were The Morton Arboretum introductions and 'New Horizon'.
  36. ^ Zetterstrom, Tom (2017). Pinchot, Cornelia C.; Knight, Kathleen S.; Haugen, Linda M.; Flower, Charles E.; Slavicek, James M. (eds.). "Report From the Street" (PDF). Proceedings of the American Elm Restoration Workshop 2016; 2016 October 25–27; Lewis Center, OH. Newtown Square, PA. United States Department of Agriculture, United States Forest Service, Northern Research Station: 119–121. doi:10.2737/NRS-GTR-P-174. OCLC 1231892730. Gen. Tech. Rep. NRS-P-174. Retrieved February 7, 2021. Consumers need to also be aware that a nursery trade mix-up a dozen years ago still plays out in the marketplace, and 'Princeton' elms continue to be sold as 'Jefferson' unknowingly by reputable nurseries from New York to Minnesota. .... National Elm Trial (NET) results were inconclusive and provided no data on 'Jefferson' due to the cultivar mix-up.
  37. ^ "Jefferson American Elm vs. Princeton American Elm". Disease-Resistant Elm Identification Guide. University of Minnesota: Urban Forestry Outreach, Research & Extension: The UFore Nursery & Lab. Archived from the original on February 7, 2021. Retrieved February 7, 2021.
  38. ^ "Elm Recovery Project". University of Guelph. Archived from the original on December 2, 2007.
  39. ^ "Scientists Breed Supertrees to Beat Dutch Elm". Canada.com. September 11, 2007. Archived from the original on April 2, 2021. Retrieved December 21, 2014 – via PressReader.
  40. ^ Sticklen, Mariam B.; Sherald, James L. (1993). Chapter 13: Strategies for the Production of Disease-Resistant Elms. Mariam B.; Sherald, James L. (eds.). Dutch Elm Disease Research: Cellular and Molecular Approaches. New York: Springer-Verlag. pp. 171–183. ISBN 9781461568728. LCCN 93017484. OCLC 851736058. Retrieved November 22, 2019 – via Google Books.
  41. ^ Newhouse, AE; Schrodt, F; Liang, H; Maynard, CA; Powell, WA (2007). "Transgenic American elm shows reduced Dutch elm disease symptoms and normal mycorrhizal colonization". Plant Cell Rep. 26 (7): 977–987. doi:10.1007/s00299-007-0313-z. PMID 17310333. S2CID 21780088.
  42. ^ Coladonato, Milo (1992). "Ulmus americana". Fire Effects Information System (FEIS). US Department of Agriculture (USDA), Forest Service (USFS), Rocky Mountain Research Station, Fire Sciences Laboratory. Retrieved December 14, 2014.
  43. ^ Ager, A. A.; Guries, R. P. (1982). "Barriers to Interspecific Hybridization in Ulmus americana". Euphytica. 31 (3): 909–920. doi:10.1007/bf00039231. S2CID 34278784.
  44. ^ Heybroek, H. M.; Goudzwaard, L.; Kaljee, H. (2009). Iep of olm, karakterboom van de Lage Landen (Elm, A Tree With Character of the Low Countries (in Dutch). Zeist, Netherlands: KNNV Uitgeverij. ISBN 978-9-0501-1281-9.
  45. ^ "Ulmus 'Hamburg'". Morton Arboretum. Archived from the original on December 27, 2014. Retrieved December 27, 2014.
  46. ^ Barnard, Edward S. (2002). New York City Trees. New York: Columbia University Press. ISBN 978-0-2311-2835-3.
  47. ^ Beveridge, Charles. "Buffalo's Park and Parkway System". Buffalo Architecture and History. Archived from the original on March 4, 2016. Retrieved December 21, 2014.
  48. ^ Trebay, Guy (February 22, 2014). "In the Treetops, a Winter Gift". New York Times. Archived from the original on December 22, 2014. Retrieved December 23, 2014.
  49. ^ Templeton, David (August 11, 2013). "Saving the Nation's Green Giants: Tall, Lush Trees". Pittsburgh Post-Gazette. Archived from the original on December 16, 2014. Retrieved December 24, 2014.
  50. ^ Manas, Steve (May 8, 2008). "Voorhees Mall Elms Add to Commencement's Ambience". Rutgers University. Archived from the original on September 30, 2011. Retrieved December 24, 2014.
  51. ^ "Elm Bark Beetle Control Program" (PDF). City of Winnipeg. August 7, 2009. Retrieved December 24, 2014.
  52. ^ Rumbolt, Colin (November 17, 2009). "Dutch Elm Vaccine Tested In Winnipeg". The Manitoban. Archived from the original on September 29, 2011. Retrieved December 24, 2014.
  53. ^ (1) "The 2012 National Register of Big Trees" (PDF). American Forests. 2012. Archived (PDF) from the original on March 15, 2013. Retrieved December 24, 2012.
    (2) "Champion Louisiana Trees". Alexandria, Louisiana: Louisiana Forestry Association. Archived from the original on November 25, 2019. Retrieved November 25, 2019.
  54. ^ Johnson, Owen (2011). Champion Trees of Britain & Ireland: The Tree Register Handbook. Kew: Royal Botanic Gardens. ISBN 9781842464526. OCLC 1023259931. Retrieved November 28, 2020 – via Google Books.
  55. ^ Mitchell, A. F.; Hallett, V. E.; White, J. E. J. (1990). Forestry Commission Field Book 10: Champion Trees in the British Isles (3rd ed.). London: Her Majesty's Stationery Office (HMSO). p. 20. ISBN 0117102865. OCLC 22783386. Archived from the original on November 26, 2019. Retrieved November 25, 2019 – via Forest Research.
  56. ^ "Penn Treaty Elm". Haverford College Arboretum. Archived from the original on December 27, 2014. Retrieved December 28, 2014.
  57. ^ a b Platt, Rutherford (1992). 1001 Questions Answered About Trees. Courier Dover Publications. p. 19. ISBN 0-486-27038-6. Archived from the original on May 6, 2016. Retrieved November 22, 2015.
  58. ^ a b Jacobson, Arthur Lee. "Arthur Lee Jacobson: Trees of the Washington State Capitol Campus". Archived from the original on October 1, 2011. Retrieved October 7, 2011.
  59. ^ "Big Day for Curio Hunter When Famous Elm is Cut". The Harvard Crimson. Harvard University. October 23, 1920. Archived from the original on June 4, 2011. Retrieved December 24, 2014.
  60. ^ Jack, J. G. (December 10, 1931). "The Cambridge Washington Elm" (PDF). Bulletin of Popular Information. Arnold Arboretum, Harvard University. Archived (PDF) from the original on March 4, 2016. Retrieved December 24, 2014.
  61. ^ a b c d "The Logan Elm". Over-land. Archived from the original on September 27, 2011. Retrieved October 6, 2011.
  62. ^ "The Roots of Tragedy". Ohio Magazine. Archived from the original on December 15, 2014. Retrieved December 14, 2014.
  63. ^ a b Sharp, David (January 31, 2010). "Do Rings of Herbie the Elm Have Age, Climate Data?". Boston.com. Associated Press. Archived from the original on December 25, 2014. Retrieved December 24, 2014.
  64. ^ "The Big Elm". University of Prince Edward Island: Island Narratives Program. Charlottetown, Prince Edward Island, Canada: University of Prince Edward Island. September 11, 2016. Archived from the original on September 11, 2016.
  65. ^ "Survivor Tree: Witness to Tragedy, Symbol of Strength". Oklahoma City National Memorial and Museum. Archived from the original on December 25, 2014. Retrieved December 24, 2014.
  66. ^ "Liberals votes against saving Parliament Hill Elm Tree". Nationalpost. National Post. Retrieved April 30, 2019.
  67. ^ "Century Old tree cut down on Parliament Hill". CBC News. Archived from the original on May 3, 2019. Retrieved April 30, 2019.
  68. ^ Russell, Nancy (October 7, 2022). "Downed Charlottetown trees get a second life after Fiona". CBC News. Retrieved June 6, 2023.
  69. ^ Platt, Bill (August 26, 2022). "West House Says Goodbye to an Old Friend". Dartmouth News. Dartmouth College. Retrieved May 30, 2023.
  70. ^ "Storm Efforts and Oval Trees".
  71. ^ "The Mall and Literary Walk". New York City: Central Park Conservancy. 2014. Archived from the original on May 31, 2014.
  72. ^ Pollak, Michael (January 11, 2013). "Answers to Questions About New York". The New York Times. Archived from the original on April 1, 2016.
  73. ^ Sherald, James L (December 2009). Elms for the Monumental Core: History and Management Plan (PDF). Washington, D.C.: Center for Urban Ecology, National Capital Region, National Park Service. Natural Resource Report NPS/NCR/NRR--2009/001. Archived (PDF) from the original on November 29, 2010. Retrieved October 14, 2010.
  74. ^ "Ulmus americana L.; Ulmus americana L.× pumila L. var. arborea". Catalogue of the Living Collections. Edinburgh, United Kingdom: Royal Botanic Garden. 2018. 19901741 and 19802124. Archived from the original on April 2, 2021. Retrieved April 2, 2021.

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Ulmus americana: Brief Summary

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Ulmus americana, generally known as the American elm or, less commonly, as the white elm or water elm, is a species of elm native to eastern North America, naturally occurring from Nova Scotia west to Alberta and Montana, and south to Florida and central Texas. The American elm is an extremely hardy tree that can withstand winter temperatures as low as −42 °C (−44 °F). Trees in areas unaffected by Dutch elm disease (DED) can live for several hundred years. A prime example of the species was the Sauble Elm, which grew beside the banks of the Sauble River in Ontario, Canada, to a height of 43 m (140 ft), with a d.b.h of 196 cm (6.43 ft) before succumbing to DED; when it was felled in 1968, a tree-ring count established that it had germinated in 1701.

For over 80 years, U. americana had been identified as a tetraploid, i.e. having double the usual number of chromosomes, making it unique within the genus. However, a study published in 2011 by the Agricultural Research Service of the USDA revealed that about 20% of wild American elms are diploid and may even constitute another species. Moreover, several triploid trees known only in cultivation, such as 'Jefferson', are possessed of a high degree of resistance to DED, which ravaged American elms in the 20th century. This suggests that the diploid parent trees, which have markedly smaller cells than the tetraploid, may too be highly resistant to the disease.

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