By FRANCES LAMBERTS
It seemed as though the American Elm were leafing out prematurely, after warm February days, very early in March. But the canopy coloration was reddish, not the dark-green of the leaves which clothe this tree later.
Dangling from pendulous stalks, the individual blossoms are small and inconspicuous but their prolific numbers make quite an announcement, evident from afar, that life is stirring in the tree. The flowers, pollinated by wind, soon set seeds and surround each of them with an oval-shaped, papery wing of translucent green color. The seed maturing within a few months and dropping by the time the tree has fully leafed out, these fruits are a popular food source for birds, mice, squirrels and other wildlife.
Elm leaves have a prominent yellow mid-vein and many parallel veins running straight from it to the leaf edge. The leaf margin is double-serrated and its sides are uneven and lopsided at the base.
The leaves are a major larval food source for Mourning Cloak, Red Admiral, Question Mark and several other eastern butterflies. Indeed, says Doug Tallamy in Bringing Nature Home, “elms support a great diversity of Lepidoptera, including several species that eat nothing else.” Among these is a moth he terms a quintessential elm specialist. Its caterpillar has doubly-toothed humps on its back and “looks just like the serrated leaves” on which it feeds. Through green coloration, habit of chomping along leaves’ mid-vein and then “disguising the feeding damage with its own body,” the larva can trick hungry birds to leave it alone.
American Elm was prominent throughout the eastern half of North America and one of the Appalachian forests’ dominant trees in earlier times. Fast growth, large size and tolerance of compacted soils, and a graceful form with wide, low-sweeping branches also made it a popular urban shade tree. But, as the Tennessee Conservationist magazine noted last year, like the American Chestnut before it, American Elm has been affected by a fungus introduced through international trade. The fungus, spread by a bark beetle and causing “Dutch Elm Disease,” has caused dramatic losses of the tree all across its range. Disease-resistant varieties have been developed, states the Missouri Botanic Garden, which “are promising but not completely immune.”
American Elm, with tree number 76 and botanic name Ulmus americana is found up-slope of the Britt Drive pathway in the Ardinna Woods Arboretum.