19. American White Elm

Also called the Soft Elm

Specimen Size: 72.1ft tall, 37.5in in diameter.

Location: South of the HUB towering over the bus shelter and shading much of the large planter there single handedly.

Historical Background: Also known as the White elm, large populations of this tree has been ravaged by Dutch elm disease brought by European shipments of wood in the 1930’s. Before then, they were commonly planted as shade trees on city streets. Although they seed prolifically at a young age, mature elms are often scarce on the landscape due to the disease. Today, a number of specimens are resistant to Dutch elm disease and continue to persist. The wood of an American Elm is moderately heavy, hard, and stiff with interlocking grain that makes it difficult to split but ideal for use in the production of hockey sticks where bending is necessary. It has also been used for production of furniture, flooring, construction, and mining timbers. The inner bark is fibrous and used to make strong ropes. Fibers obtained from the stems have been used to make beige paper. Parts of the elm is also used medicinally by Native Americans to treat broken bones, wounds, and stomach issues. 

Non-native

Native Range: Eastern North America 

Identifying Features: The American White Elm may be contrasted with the English Elm seen earlier in the tour. Mature specimens generally exhibit far less apical control, with many graceful spreading branches drooping at the ends forming a massive flat topped and vaselike crown generally much wider than it is tall. The leaves are Dark green and rough on top, growing in two rows like their European cousins. They too are doubly toothed with parallel side veins. The base of the American Elm is greatly buttressed and light gray deeply furrowed bark which forks into scaly ridges. Seed wings are similarly notched at the tip, but unlike the English Elm seeds those of the American Elm occur towards the center of the wing and are more likely to be reproductively viable.

Identifying Features In Depth:

1. Form: Large and spreading, with a flat topped vase shaped crown of many branches that droop and is extremely distinct. Grows to a height of 100’ (30m) and diameter of 4’ (1.2m), although in some cases diameter can be even larger. Mature specimens such as this are quite rare since the appearance of Dutch Elm disease in the Americas.

2. Leaves: Grow in two rows along the branch to a length of 3-6” (7.5-15 cm) and width of 1-3” (2.5-7.5 cm). Leaves are rough on top, and a dark green color, paler on the bottom and sprouting small hairs. They are elliptical and come to an abrupt sharp point, with doubly toothed margins along the edges and pinnate venation. The petiole is about 6mm in length and hairy.

3. Bark: Light gray and deeply furrowed, exhibiting broad forking scaly ridges. Twigs are brownish, slender, and hairless in nature.

4. Reproductive Bodies: Flowers grow clustered into short stalked fascicles of 3-4 and appear prior to leafing in spring. They are greenish in color and about 3mm wide. These give way to winged fruit with long flat elliptical single seeded keys. The wings are hairy on the edges and have a notch at the tip. The seed is closer to the center of the wing and attaches in clusters via a stalk about 1.3 cm in length.