American elm (Ulmus americana): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Ulmus americana L., elm family
Other names	White elm, water elm, soft elm and Florida elm (Silvics)
Native status, USDA PLANTS	Native in Canada and in the lower 48 states
Size, Silvics	On good sites in dense stands 30 to 38 m (98 to 125 ft) tall and 122 to 152 cm (48 to 60 in) in diameter; on very wet or very dry soils often 12 to 18 m (40 to 60 ft)
Age, Silvics	Often 175 to 200 years, with some older than 300 years
Green weight of the wood, NRS-38	56 lb per cubic foot, without bark

Native range

The Silvics of North America handbook (Agriculture Handbook 654, 1990) says American elm is found throughout eastern North America, from Cape Breton Island and 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. Its opening paragraph says the species is most notable for its susceptibility to Dutch elm disease, and that because of it American elms make up a smaller share of the large-diameter trees in mixed forest stands.

Size, form and age

Silvics says American elm seldom grows in pure stands. In open-grown or sparse stands the trees usually fork near the ground and form wide arching crowns. In dense stands on good sites the handbook records a clear trunk of 15 m (49 ft). Before Dutch elm disease, it says, the tree was prized as a street tree because it was fast growing, hardy and tolerant of stress, with a characteristic vase-like crown.

Flowers and roots

The handbook says the flower buds swell as early as February in the South and as late as May in Canada, and the flowers appear 2 to 3 weeks before leaf flush. They are typically perfect, on drooping stalks about 2.5 cm (1 in) long, in clusters of three or four, with bright red anthers. Seed fall is usually complete by mid-March in the South and mid-June in the North. On rooting, Silvics says the depth varies with soil: within 0.9 to 1.2 m (3 to 4 ft) of the surface in heavy, wet soils, 1.5 to 3.0 m (5 to 10 ft) on drier medium-textured soils, and a taproot of 5.5 to 6.1 m (18 to 20 ft) in deep dry sands in the Dakotas. It adds that where trees are planted between street and sidewalk, buttress roots often result from inadequate soil aeration.

Wood

The Wood Handbook (FPL-GTR-282, 2021) says elm sapwood is nearly white and heartwood light brown, often tinged with red. It places American and slippery elm in the soft elm class, and describes the wood as moderately heavy with high shock resistance, moderately hard and stiff, with excellent bending qualities. Silvics adds that the wood has interlocked grain and is difficult to split. The Wood Handbook says elm lumber and veneer are used mostly for furniture and decorative panels.

Wood Handbook figure	Green	At 12% moisture content
Specific gravity (Table 5-3b)	0.46	0.50
Modulus of rupture, lbf per square inch (Table 5-3b)	7,200	11,800
Side hardness, lbf (Table 5-3b)	620	830
Moisture content of green wood, percent (Table 4-1)	95 heartwood, 92 sapwood	Not applicable

The green weight of the wood is in the NRS-38 table, the same figure used in the log weight calculator.

Pests and diseases the agencies name

Silvics says Dutch elm disease reached the United States in 1930 in a shipment of elm logs from Europe and had spread to 41 states. It names the fungus Ceratocystis ulmi, carried by the smaller European elm bark beetle and the native elm bark beetle, and says the disease is characterized by gradual wilting and yellowing of the foliage, usually followed by death of the branches and eventually the whole tree. The Wood Handbook says Dutch elm disease and phloem necrosis have killed hundreds of thousands of trees and that the International Union for Conservation of Nature lists American elm as endangered.

Other wilts and dieback. Phloem necrosis, spread by the whitebanded elm leafhopper and through root grafts, which Silvics says is detected by flagging or browned leaves; Verticillium wilt; and diebacks from Cephalosporium and Dothiorella.
Cankers and rots. Cankers from Nectria, Sphaeropsis ulmicola and Phytophthora inflata; elm wetwood; and the wood rot fungi Pleurotus ulmarius, Pleurotus ostreatus, Armillaria mellea, Ganoderma applanatum and Phellinus igniarius.
Leaf and twig. A leaf black spot, a twig blight and elm mosaic virus.
Insects. The carpenterworm in the sapwood; the spring cankerworm, forest tent caterpillar, elm leaf beetle, whitemarked tussock moth and elm spanworm among the defoliators; the elm scurfy scale and European elm scale; and the elm cockscombgall aphid, which the handbook says forms leaf galls but does little damage to the tree.

The guide on reporting a pest in the United States gives the office that takes sightings of regulated pests, and pests and diseases by country sets out which ones agencies regulate. Who may apply pesticides is in pesticide licences by country.