American elm

American elm
	American elm ( Ulmus americana )
Systematics
	Eurosiden I
Order :	Rose-like (rosales)
Family :	Elm family (Ulmaceae)
Subfamily :	Ulmoideae
Genre :	Elms ( ulmus )
Type :	American elm
Scientific name
	Ulmus americana
	L.

The American elm ( Ulmus americana ), also called white elm , is a species of the elm genus ( Ulmus ) within the elm family (Ulmaceae). It is widespread in North America . It is used as an ornamental plant and in landscaping. American elm populations were severely decimated in the second half of the 20th century due to the fungus Ceratocystis ulmi ( Dutch elm disease ).

description

Illustration from The North American Sylva

bark

Stalked simple leaf

Branch with winter buds, they have the same orientation as the branch section below

Underside of the leaf: The veins are easy to see

Illustration depicting the inflorescence and the fruit

Samara

The specimens of the American elm can be 175 to 200 old; a few single specimens are reported to be around 300 years old.

Appearance

The American elm grows as a deciduous, deciduous tree . In dense forests, stature heights of 30 to 36 meters and breast height diameters (BHD) of 122 to 152 centimeters are achieved. In average locations, stature heights of around 24 meters are common, but in very moist or very dry locations, fully grown specimens only reach stature heights of 12 to 18 meters.

The root system is different depending on the location. In heavy, moist soils , the root system is widespread with most roots at depths of 1 to 1.2 meters. On the drier soils Ulmus americana develops a deep-reaching tap root .

Trunks 15 to 18 meters long are formed in forests. Free-standing specimens have branches from a height of 3 to 6 meters above the ground and form a widely spread treetop . The crown diameter can be over 30 meters.

The light brown to dark gray bark is deeply fissured and detaches from the trunk in irregular stripes that curve at their ends. The inner bark consists of alternating brown and white layers. The wood is soft. The bark of the twigs is brown and hairy to bald. The branches are hanging and older branches are smooth, not winged. The red-brown winter buds are conical or narrow-egg-shaped with a pointed upper end and more or less hairy or glabrous. The branches end with leaf scars, so the "terminal bud" is not really terminally a little larger than the lateral ones.

leaf

The alternate leaves arranged on the branches are divided into a petiole and a leaf blade. The bald to downy hairy petiole is about 5 millimeters long. The simple leaf blade is usually 8.6 to 12.5 (7 to 14) centimeters in length and 3 to, usually 4.2 to 7 centimeters in width, elliptical or sometimes oblong, oval to oblong-obovate with slate Spreading base and pointed to pointed upper end. The leaf margins are strongly double serrated. The underside of the leaf including the leaf veins is sparsely hairy and tufts of hair are in the branches of the veins. The upper side of the leaf is bare to scaly. There is pinnate veins . The two membranous stipules fall off early and leave a short scar on both sides of the leaf.

Inflorescence and flower

The bundled inflorescences are shorter than 2.5 centimeters and contain three to four flowers. There are two membranous bracts . The flowers and fruits hang on 7 to 17 millimeter long, thin stems that extend to a maximum of 25 millimeters when the fruit is ripe.

The flower buds are bare. The mostly hermaphrodite flowers have a simple flower envelope . The seven to nine inconspicuous green colored and above their center red tinted bracts are fused and bell-shaped. The calyx is somewhat asymmetrical and ends in seven to nine short calyx lobes; the edges are ciliate. There are seven to nine stamens . The stamens are flat and the anthers are bright red. The stamp is light green. The relatively short stylus ends in a bifurcated, white-lashed, deep split scar scar.

fruit

There are wing nuts formed (Samara). The thickened nuts, which are tan-colored or cream-yellow, sometimes reddish-purple, spotted when ripe are elliptically elongated or egg-shaped with a length of 0.9 to 1.3 centimeters and a width of 0.6 to 0.8 centimeters; their edges are densely ciliated yellow to white and their surfaces are bare. The membranous wings are relatively narrow with about 1 millimeter. The top of the wing is deeply notched.

Chromosome set

The basic chromosome number is x = 14; there is often tetraploidy with chromosome number 2n = 56. A smaller part of the populations is diploidy before.

Phenology

Seedlings

The flowering time , fruit ripening and the falling of the diaspores take place in spring and vary by about 100 days between the Gulf Coast and Canada. The flower buds swell in the southern states early in February and most recently in May in Canada. The anthesis is two to three weeks before the leaves develop. The fruits ripen while the leaves unfold or shortly afterwards. The diaspores spread as soon as the fruits are ripe and the spread ends in the south in mid-March and in the north in mid-June.

Beetle larva of Monocesta coryli on a deciduous leaf of Ulmus americana

ecology

In Ulmus americana is a phanerophytes . There is a vegetative reproduction , for example look for stick rash.

The earliest specimens of the American elm can flower when they are 15 years old, but they are only fully productive when they are 40 years old. The American elm is basically self-sterile. Frosts in spring destroy flowers and fruits.

The spread of the diaspores , it is the wing nuts (samara), is carried out by the wind ( anemochory ). Most diaspores are moved no more than 90 meters from the mother tree, but some are moved 400 meters. The diaspores are spread many miles through the water by specimens that stand next to rivers.

The germination of seeds is carried out is epigeal. Germination occurs early after it has spread, but some seeds remain viable in the soil until the following spring.

The Ulmus americana provides nesting places for many animals . The flower buds, flowers and fruits are eaten by many animals.

Distribution area 1938

Planted in spring

Illustration from A guide to the trees , Tafel LVI

Occurrence

The original wide distribution area of Ulmus americana extends in North America from the eastern and western Canadian provinces of New Brunswick , Ontario , Prince Edward Island , Quebec , Manitoba , Saskatchewan and in the US states of Montana, Wyoming , Illinois , Iowa , Kansas , Minnesota , Missouri , Nebraska , North Dakota , South Dakota , Oklahoma , Wisconsin , Connecticut , Indiana , Maine , Massachusetts , Michigan , New Hampshire , New Jersey , New York , Ohio , Pennsylvania , Rhode Island , Vermont , West Virginia , Texas , Alabama , Arkansas , Delaware , Florida , Kentucky , Louisiana , Maryland , Mississippi , North Carolina , South Carolina , Tennessee , Virginia , District of Columbia . It has run wild in Idaho for the past 100 years.

It thrives in alluvial forests , swamp forests, deciduous woodlands, along fences, pastureland , old fields and on wasteland at altitudes from 0 to 1400 meters.

Ulmus americana occurs in the entire range mostly in plains and lowlands, but is not limited to these areas. It usually does not occur in deep swamps. At higher altitudes in the Appalachian Mountains , it often only occurs near large rivers and rarely thrives at altitudes above 610 meters. But in West Virginia it still thrives at altitudes of 760 meters. In the lake and central US states, it thrives on plains and moraine hills as well as in the lowlands and on the edges of swamps . Along the north-western limit of distribution, it usually only thrives on valley floors along watercourses.

Ulmus americana can be found on many types of soil . It thrives best in rich, well- drained clay soils . Soil moisture is crucial for Ulmus americana to grow . Ulmus americana can cope with a wide variety of soil pH values. At the edges of the swamp the pH is quite acidic and on prairie soils it is quite alkaline. The pH values range from 5.5 to 8.0 in the entire distribution area. The leaf litter of Ulmus americana decomposes much faster than many other North American tree species. Many important nutrients are made available to the soil.

In the natural range of Ulmus americana , the climate varies from warm and humid in the southeast to cold and dry in the northwest. Average temperatures range from -18 ° C and below in Canada to 16 ° C in central Florida in January; July from 16 ° C in Manitoba to 27 ° C in the southern states. The annual maximum is between 32 ° C to 35 ° C in the northeast and 38 ° C to 41 ° C in the south and west. The annual minimum is between −40 ° C to −18 ° C in the north and −18 ° C to −1 ° C in the south.

Annual rainfall varies from a scant 380mm in the northwest to a plentiful 1520mm on the Gulf Coast. In the central part of the distribution area, the annual precipitation is between about 760 and 1270 mm. In the largest part of the distribution area, the precipitation occurs mainly in the warm season from April to September. Annual snowfall ranges from no snow in Florida to 200 cm in the northeast; few areas mainly around the Great Lakes receive 254 to 380 cm of snow per year. The average frost-free period is around 80 to 160 days in the northernmost part of the US states and Canada, and around 200 to 320 days in the Gulf Coast and the southern states.

Systematics

The first publication of Ulmus americana was in 1753 by Carl von Linné in Species Plantarum , 1, p. 226. A homonym is Ulmus americana Marshall . Synonyms for Ulmus americana L. are Ulmus americana var. Aspera Chapm. , Ulmus americana var. Floridana (Chapm.) Little , Ulmus floridana Chapm. No subtaxa are accepted.

Ulmus americana belongs to the section Blepharocarpus from the subgenus Oreoptelea in the genus Ulmus within the family Ulmaceae .

American elm planer

Avenue trees in winter

The 'Valley Forge' variety, resistant to Dutch elm disease

Valley Forge leaves in autumn

use

The wood of the American elm is coarse-grained, heavy and strong. It is not durable and will distort and splinter badly when dried. The wood is used to make boxes, boxes, baskets, barrels, furniture, agricultural implements and coffins. The veneer is used for furniture and paneling. The American elm also provides firewood .

The American elm is planted to protect against erosion and wind protection. The mostly flat and widespread root system makes the American elm fairly windproof. The American elm can be propagated vegetatively by cuttings, but with more or less good results.

The inner bark was used for many decorative purposes by the Indians of the southeastern United States .

It is used as an ornamental plant. There are a few varieties and hybrids . American elm trees line many streets and provide shade. Their particularly good properties for use on roads are their rapid growth, hardness and stress tolerance.

The indigenous peoples used the bark to make canoes, ropes and other utensils.

Diseases

The fungus Ceratocystis ulmi spread in the USA from around 1930. By the fungus infestation is population of the American elm been decimated by half since 1976th This fungus clogs the water-carrying vessels of the tree, leads to withering and ultimately death of the affected branches and ultimately the whole tree. Bark beetles spread the disease from specimen to specimen. Spraying insecticides against the beetles is only a temporary measure. A permanent treatment is currently not known. Therefore, the stocks will continue to be decimated, especially since the American elm is particularly vulnerable.

Attempts to avoid this susceptibility by crossing with other elms have so far not led to resounding success, because resistant species are also fraught with disadvantages. The Siberian elm, for example, lacks the symmetrical growth and the wood is much more brittle and splinters easily.

Against elm disease resistant varieties, for example, the 'Princeton' and 'Valley Forge'.

Symbolism and paintings

The American elm is the official state tree of the US states of Massachusetts and North Dakota .

The American elm is shown in some of the paintings.

Frederick Childe Hassam : "Washington Arch, Spring" 1893
Frederick Childe Hassam: "Church at Old Lyme" 1905
Frederick Childe Hassam: "The East Hampton Elms in May" 1920
George Inness : "Old Elm at Medfield"

Common names in other languages

Common names in other languages are:

English language : American elm, water elm, white elm, soft elm, Florida elm
French language : orme d'Amérique

The "Grayson Elm" in summer 2016

Special specimens

There are many individual specimens of the American elm that are particularly well known; some who are particularly old, have a particular habit, are particularly tall, have been given a name or have a particular story known about.

swell

Calvin F. Bey, 1990: Ulmus americana- American Elm. In: Russell M. Burns, Barbara H. Honkala: Hardwoods. Silvics of North America. Washington, DC: United States Forest Service (USFS), United States Department of Agriculture (USDA). Northeastern Area State and Private Forestry (www.na.fs.fed.us).
Milo Coladonato, 1992: Ulmus americana - data sheet from Fire Effects Information System. of the United States Forest Service.
Susan L. Sherman-Broyles: Ulmus. : Ulmus americana - the same text online as the printed work , In: Flora of North America Editorial Committee (ed.): Flora of North America North of Mexico. Volume 3: Magnoliophyta: Magnoliidae and Hamamelidae. Oxford University Press, New York and Oxford, 1997, ISBN 0-19-511246-6 .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Ulmus americana in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved November 9, 2016.
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w Calvin F. Bey, 1990: Ulmus americana- American Elm. In: Russell M. Burns, Barbara H. Honkala: Hardwoods. Silvics of North America. Washington, DC: United States Forest Service (USFS), United States Department of Agriculture (USDA). Northeastern Area State and Private Forestry (www.na.fs.fed.us).
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Milo Coladonato, 1992: Ulmus americana - data sheet at Fire Effects Information System. of the United States Forest Service.
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l data sheet at Jepson eFlora .
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z Susan L. Sherman-Broyles: Ulmus. : Ulmus americana - the same text online as the printed work , In: Flora of North America Editorial Committee (ed.): Flora of North America North of Mexico. Volume 3: Magnoliophyta: Magnoliidae and Hamamelidae. Oxford University Press, New York and Oxford, 1997, ISBN 0-19-511246-6 .
^ ^A ^b ^c Edward A. Cope, 2000: Ulmus americana - Datasheet Know Your Trees at Cornell University.
↑ American elm - Ulmaceae - Ulmus americana L. - Datasheet of the Department of Forest Resources and Environmental Conservation at Virginia Tech.
↑ Ulmus americana at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
^ AT Whittemore, RT Olsen: Ulmus americana (Ulmaceae) is a Polyploid Complex. In: American Journal of Botany , Volume 98, Issue 4, 2011, pp. 754-760. doi : 10.3732 / ajb.1000372
↑ Carl von Linné 1753: scanned in at biodiversitylibrary.org .
↑ Ulmus americana at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed November 7, 2016.
↑ American elm - data sheet of the Morton Arboretum.

Web links

Commons : American elm ( Ulmus americana ) - Collection of images, videos and audio files

[GRIN-1] ↑ ^a ^b ^c ^d ^e ^f ^g Ulmus americana in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved November 9, 2016.

[Bey1990-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w Calvin F. Bey, 1990: Ulmus americana- American Elm. In: Russell M. Burns, Barbara H. Honkala: Hardwoods. Silvics of North America. Washington, DC: United States Forest Service (USFS), United States Department of Agriculture (USDA). Northeastern Area State and Private Forestry (www.na.fs.fed.us).

[FEIS-3] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Milo Coladonato, 1992: Ulmus americana - data sheet at Fire Effects Information System. of the United States Forest Service.

[Jepson-eFlora-4] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l data sheet at Jepson eFlora .

[FoNA-5] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z Susan L. Sherman-Broyles: Ulmus. : Ulmus americana - the same text online as the printed work , In: Flora of North America Editorial Committee (ed.): Flora of North America North of Mexico. Volume 3: Magnoliophyta: Magnoliidae and Hamamelidae. Oxford University Press, New York and Oxford, 1997, ISBN 0-19-511246-6 .

[CornellUniversity-6] A ^b ^c Edward A. Cope, 2000: Ulmus americana - Datasheet Know Your Trees at Cornell University.

[VirginiaTech-7] American elm - Ulmaceae - Ulmus americana L. - Datasheet of the Department of Forest Resources and Environmental Conservation at Virginia Tech.

[IPCN-8] Ulmus americana at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis

[WhittemoreOlsen2011-9] AT Whittemore, RT Olsen: Ulmus americana (Ulmaceae) is a Polyploid Complex. In: American Journal of Botany , Volume 98, Issue 4, 2011, pp. 754-760. doi : 10.3732 / ajb.1000372

[Linné1753-10] Carl von Linné 1753: scanned in at biodiversitylibrary.org .

[Tropicos-11] Ulmus americana at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed November 7, 2016.

[MortonArboretum-12] American elm - data sheet of the Morton Arboretum.