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American Elm |
Once a very popular and long-lived (300+ years) shade and street tree, American Elm suffered a dramatic decline in the 1950's with the infestation of Dutch elm disease, a fungus spread by a bark beetle. The wood of American Elm is very hard and was a valuable timber tree used for lumber, furniture and veneer. The Indians once made canoes out of American Elm trunks, and early settlers would steam the wood so it could be bent to make barrels and wheel hoops. It was also used for the rockers on rocking chairs. |
Morton Arboretum accessions 604-25*1, 2 & 3, are from grafts done 83 years ago.
| These three outstanding American Elms display the classic vase-shape of the species. The Morton Arboretum is one of the largest living Ulmus collections in the world (more than 30 species, in addition to numerous infraspecific taxa, hybrids, and cultivars) and has the source of numerous elm cultivars. |
Leaf: alternate, simple, ovate to oblong, 3 to 5 inches long, 1 to 3 inches wide, margin coarsely and sharply doubly serrate, base conspicuously inequilateral, upper surface green and glabrous or slightly scabrous, paler and downy beneath. This native North American tree grows quickly when young, forming a broad or upright, vase-shaped silhouette, 80 to 100 feet high and 60 to 120 feet wide. Trunks on older trees could reach to seven feet across. The six-inch-long, deciduous leaves are dark green throughout the year, fading to yellow before dropping in fall. In early spring, before the new leaves unfold, the rather inconspicuous, small, green flowers appear on pendulous stalks. These blooms are followed by green, wafer-like seedpods which mature soon after flowering is finished and the seeds are quite popular with both birds and wildlife. Trees have an extensive but shallow root system. 
American Elm in glorious yellow autumn colors,
Morton Arboretum acc. 170-U*4, age unknown.
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When I was a child in the 1950's, Thacker Street in Des Plaines, Illinois, was lined with huge Elm trees. We walked to school shaded by those magnificent trees; they were so tall, their branches overarched the street completely. It was a wonderful walk then, and especially in fall when our mornings were bathed in yellow light filtering through the glorious butter yellow foliage. Of course, we gathered leaves to take into school with us, to trace and do rubbings with fat Crayons from our (newly introduced) 64 packs. But when the school year started in 1960, those trees had all been cut down, victims of Dutch Elm Disease. It was so sad, and now we walked under blazing sun and boy, did we miss those trees. Similar scenarios are now playing themselves out amongst the lodgepole pine and ash trees of North America. |
Buttery yellow fall foliage and an open, vase like habit - what's not to like?
The Morton Arboretum, at Lisle, Illinois, is home to the largest Elm collection in North America. Under study, the collection includes almost all of the 22 Elm species native to China, a dozen of which show resistance to Dutch elm disease and elm yellows. The Arboretum in past years has bred and marketed five new elm varieties resistant to Dutch elm disease. The 12 species being studied are: the Bergmann (Ulmus bergmanniana), Taihang Mountain (U. taihangshanensis), Tibetan (U. microcarpa), Anhui (U. gaussenii), Hebei (U. lamellosa), Harbin (U. harbinensis), corkbark (U. propinqua var. suberosa), plum-leaved (U. prunifolia), Chenmou (Ulmus chenmoui), Gansu (Ulmus glaucescens var. lasiocarpa), chestnut-leaved (U. castaneifolia) and Father David (U. davidiana var. mandshurica) elms. These 12 Chinese trees are virtually unknown in the U.S., but are under close study at the arboretum. Dendrologist Emeritus and former research director Dr. George Ware, and Arboretum Assistant Director of Collections Kunso Kim are responsible for their observation and data collection. Their efforts may help ameliorate the effects of numerous maladies affecting trees around the world, such as Emerald Ash Borer, Oak wilt, Asian Longhorned Beetle, Pine Sawyer Beetle, et al. "These and other problems underscore the urgent need for the Arboretum and others to continue seeking new species for urban use," Kim says. The average lifespan of an urban tree is fewer than 10 years, according to Ware. But planting hardier trees increases the likelihood of a longer life span and a greener world - a goal that has never been more important than now, with climate change upon us. [2] |
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