American Elm

Order: Urticales
Family: Ulmaceae
Genus: Ulmus
Species: americana

external image American_Elm_tree.jpgexternal image american_elm_leaf.jpgexternal image american_elm_fruit.JPG

Identifying Characteristics
  • American Elms can be found all over eastern North American; from the Atlantic Ocean to just past the Dakotas, Nebraska, Kansas, Oklahoma, and central Texas, from the Gulf of Mexico (excluding southern Florida) to Nova Scotia, southern Ontario, southern Manitoba, and southeastern Saskatchewan.
  • This is a deciduous tree that can reach a height of 100 feet and attain a trunk 4 feet in diameter at chest height (d.b.h.). However, elms of this size are rare today, as most have been killed by the Dutch Elm Disease.
  • The leaves are alternate, between 2.75 and 8 inches long, with double-serrate edges, and an oblique base.
  • The flowers are perfect (having both male and female parts), small, and purple-brown in color.
  • The 4-5 mm seeds are encased in an oblong, flat, wing-like fruit, which are about 0.5 inch wide and 0.75 inch long.
  • Larger trees are characterized by an attractive vase-like crown.
Special Adaptations
  • The American Elm is a hardy, moderately shade, flood, and drought-tolerant species, which enables it to grow in a wide variety of habitats:
    • It is able to tolerate a wide range of rainfall, from 15 to 60 inches annually.
    • It is also able to tolerate a wide range of snowfall, from 0 to 150 inches annually, as well as a frost-free period as short as 80 days.
    • It has an adaptable rooting habit, which allows it to grow in soil groups as varied as well-drained sands, organic bogs, poorly-drained clays, silts, prairie loams, and just about everything in between.
  • Elms are able to produce seeds as early as age 15 to as old as 300. The seeds are winged, which allow for a wide dispersal; generally 300 feet to 1/4 mile, or even several miles if the seeds become waterborne in a stream.
  • Seed germination generally occurs soon after contact with the ground, although some seeds are able to lie dormant until the following spring.
  • The "crown" structure was attractive and useful for shade, so many trees were left standing as towns went up around them due to the shade they provided to the streets.
  • Elm grows with an interlocked grain, and the wood is heavy, hard, and stiff. Because of these traits, it has been prized for the creation of furniture, flooring, timbers, and hockey sticks. While this value leads to more being removed from the forest, it also results in greater efforts to help new elms grow.

References
Bey, C.F. (1990, December). American Elm. Silvics of North America, 2. Retrieved July 16, 2011, from http://www.na.fs.fed.us/pubs/silvics_manual/volume_2/ulmus/
americana.htm

Wikipedia. (2011, July 6). Ulmus americana. Retrieved July 16, 2011, from http://en.wikipedia.org/wiki/Ulmus_americana