American Elm - Ulmus americana
(see State Rank Reason below)
MNPS Threat Rank
State Rank Reason (see State Rank above)
Ulmus americana occurs in hardwood draws on the eastern edge of Montana. Native stands have been affected by woodcutting, overgrazing by livestock, and can exhibit significant dieback that may be related to drought or late spring freezes. Yet trees re-sprout after fire or harvesting. It has commonly been planted as an ornamental. While Dutch elm disease (Ceratocystis ulmi) has impacted planted trees in towns, there are no reports of it killing native populations in eastern Montana. Populations appear stable, but current data is needed on locations, population age structure and sizes, and threats.
- Details on Status Ranking and Review
ScoreF - 20,000-200,000 sq km (~8,000-80,000 sq mi)
Area of Occupancy
ScoreD - 6-25 4-km2 grid cells
Number of Populations
ScoreC - 21 - 80
Number of Occurrences or Percent Area with Good Viability / Ecological Integrity
ScoreC - Few (4-12) occurrences with excellent or good viability or ecological integrity
ScoreC - Moderate. Generalist or community with some key requirements scarce
ScoreD - Low
CommentThreat categories include: Logging & wood harvesting. Hardwood draws in eastern Montana are the source of fenceposts and firewood, although stumps can sprout back from cuttings.
Trees to 15 m with gray to brown, fissured bark. Twigs pubescent with acute buds. Leaf blades elliptic with an asymmetric base, 7–12 cm long, scabrous above with twice serrate margins. Flowers on drooping pedicels 1–2 cm long; calyx with 7 to 9 lobes; anthers red. Samaras ovate, yellowish, about 1 cm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
Easternmost tier of counties in MT; southern Canada east from MB to NB and NS; throughout throughout eastern US east of the Longitude 100 W (Sherman-Broyles et al. 1997 in Fl. N. Amer. Vol. 3).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
In Montana it grows in woodlands within ravines or along rivers and streams; plains to eastern deciduous forests (Sherman-Broyles et al. 1997 in Fl. N. Amer. Vol. 3).
In Montana American elm can be co-dominant with green ash (Fraxinus pensylvanica). Where they both occur American elm averaged 32% in canopy cover in eastern Montana and 29% in southwestern North Dakota (Lesica and Marlow 2013).
It is shallow-rooted and grows on floodplains (Lesica and Marlow 2013). Flowers develop before the leaves bud out in late May (in Montana), and winged seeds disperse in June (in Montana) (Lesica and Marlow 2013). It can sprout from the base when cut or burned.
In Montana American elm trees can reach 100 feet in height and 70 inches in diameter (Lesica and Marlow 2013). It is believed to be capable of living to 200 years (Lesica and Marlow 2013). Its wood is hard and strong; structurally trees often exhibit large-diameter branches and many small twigs with few intermediate branches (Lesica and Marlow 2013). It was commonly planted as an ornamental (Lesica and Marlow 2013), particularly along roads and boulevards.
Within green ash woodlands, American elm are susceptible to dieback, which may be related to drought, late-spring freezes, or another cause (Lesica and Marlow 2013).
Throughout much of the U.S. Dutch elm disease (Ceratocystis ulmi) has killed native and planted elms. In eastern Montana many of the planted elms have succumbed to Dutch elm disease, but there have been no reports from native stands (Lesica and Marlow 2013).
- Literature Cited AboveLegend: View Online Publication
- Lesica, P. and C. Marlow. 2013. Green Ash Woodlands, A Review. Research Bulletin No. 4601. Montana State University Extension. Bozeman, MT. 19 pp.
- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Sherman-Broyles, S. L., W. T. Barker, and L. M. Schulz. 1997. Ulmaceae (pp. 368-371). In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America north of Mexico. 20+ volumes. New York and Oxford. Volume 3. 590 pp. + xxiii.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Little, E.L., Jr. 1979. Checklist of United States trees (native and naturalized). Agriculture Handbook No. 541. U.S. Forest Service, Washington, D.C. 375 pp.