White Elm
Ulmus americana

Location in Ontario
White Elm trees grow throughout the Deciduous Forest Region, and further north. It grows on wet, well drained soil or sand. Today, due to Dutch Elm Disease, White Elm is mostly an understorey tree.


Magnificent White Elm, Essex County
 
Genus Ulmus
The leaves of Elm are asymmetrical. The overall form of Elm trees is an umbrella shape, White Elm with the most pronounced. Elms are monoecious with perfect flowers in dense clusters. They appear in very early spring. Seeds are nutlets contained within a thin wing (samara). Nutlets are deeply notched and fall off in May. In Ontario, this genus includes Rock, Slippery and White Elm. Many Elm trees died due to Dutch Elm Disease (see Tree Diseases).

TREE FACT: Elms flower very early in the spring, second only to Red and Silver Maples.

In the Landscape
White Elm is one of Ontario's largest trees, reaching 35 metres and living to 200 years of age. If an Elm tree is planted, care must be taken to avoid Dutch Elm Disease. White Elm is a fast-growing large tree with a distinctive umbrella shape that provides deep shade.


A group of White Elm in winter, Norfolk County

Leaves
White Elm leaves are simple, with double teeth. The leaves are asymmetrical. Leaves decompose rapidly and have a relatively high content of potassium and also of calcium. Leaves turn yellow to brown in the fall.
Bark: The bark is mottled gray and scaly. The branches are arched and "weeping" downward, giving an overall umbrella-shaped form.
Flowers
White Elm is monoecious with perfect flowers. Elm flowers are tiny and light coloured, and found in dense clusters. They appear in very early spring before the leaves. Flowers are wind pollinated.
Fruit
White Elm seeds are samaras that are deeply notched. Fruit ripens quickly after pollination. White Elm produces fruit after 15 to 40 years of growth with bumper crops of seeds every 1 to 3 years.

Wood
Elm wood is hard and heavy. White Elm has a beautiful double grain. Due to its hardness, Elm was favoured for wheels, hockey sticks and boat frames.
Specific gravity: 0.64
Janka Hardness:
830 lb
Wood Comparison Chart


White Elm starting to turn colour, Norfolk County

Genetics
White Elm is tetraploid with 56 chromosomes, while all other species of Ulmus are diploid, with 28 chromosomes. Because of this, hybridization of White Elm with other Ulmus species is mostly unsuccessful. This has resulted in little success with finding a hybrid which is resistant to Dutch Elm Disease.   


Side by side young White Elms, Norfolk County

Link to United States Forest Service Silvics Manual for White Elm.

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