The American elm tree (Ulmus americana) is a species belonging to the elm family that at one time was a dominant shade tree in most of the Eastern United States. Unfortunately, Dutch elm disease, a fungal malady transmitted by certain kinds of beetles to the tree, has wiped out many elms. The leaves of the American elm possess certain characteristics that will enable you to identify this tree.
The Ohio Department of Natural Resources website states that the size of elm leaves can vary significantly from one elm to another. The leaves can be as small as 3 inches in length, while some can be close to 6 inches long. Elm leaves are anywhere from one inch wide to as wide as 3 inches.
Botanists use the term obovate to describe the shape of leaves like those of an American elm. The leaves are oblong but somewhat oval at the same time, tapering down to a point at the end. The base of the leaf where it attaches to the stem is asymmetrical in nature. One side extends down to where the leaf joins the stem, while the other does not quite reach that point.
According to the University of Florida Institute of Food and Agricultural Sciences website, an American elm leaf has an upper surface that is a dark green color. The underside of the leaf will be paler than the top side. American elm leaves can change in the fall to shades of green, such as chartreuse. In some instances, the leaves will turn to a yellowish hue.
The edges of an elm leaf have double serrations. These look like small teeth that exist all along the margins of the leaf. A series of obvious veins run throughout the elm leaf. A main vein runs north and south on the leaf through its center, with many prominent veins fanning off from the middle one and making their way to the sides of the leaf. The upper surface of American elm leaves is typically slightly rough to the touch. The undersides feature minute soft hairs.
The elm is capable of reaching heights of 100 feet, but Dutch elm disease allows few specimens to do so. Most suffer from its effects when the tree is about 40 feet tall. The elm begins to die when the fungus that causes the disease plugs up the plant's vascular system. The deprivation of nutrients to the branches eventually strips the limbs of the leaves and in time kills the tree.