Forest Preserve District of Cook County, Illinois
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Native Shade Trees to Replace Elms
Nature Bulletin No. 694   November 17, 1962
Forest Preserve District of Cook County
Seymour Simon, President
Roberts Mann, Conservation Editor

NATIVE SHADE TREES TO REPLACE ELMS
If you are fond of trees it is saddening to visit Rockford, Dixon, Springfield, Champaign-Urbana, and many other Illinois communities. Streets that used to be shaded by rows of stately graceful elms with arching limbs forming canopies like a cathedral roof, are denuded now or lined with their gaunt skeletons.

Champaign originated as a station on the Illinois Central railroad which, in 1856, had been completed across the flat treeless prairie just west of Urbana, a town founded in the late 1830's. When the University of Illinois was established there in 1867 the board of trustees adopted a plan 'to transform this prairie landscape into a campus". As the principal species of shade tree to be planted, it designated the American elm -- "the tree that like a fountain rises".

That was a wise choice in those days. Native and abundant on bottomlands, young elms were easy to transplant, grew rapidly, and would become tall graceful trees in keeping with the dignity of a campus and ideal for shading big homes on residential streets. Sturdy and resilient, they would be less subject to damage from storms than most fast-growing trees; also, then, they were comparatively free from diseases and insect pests.

In 1930 a dying elm in Cleveland, Ohio, was found to be infected with the fatal Dutch elm disease described in our bulletin No. 411. Uncontrolled and carried by bark beetles, it spread until, in 1951, two infected elms were discovered in Urbana and on the university campus. Today there are 98 survivors in Champaign and Urbana. On the campus, where 2267 elms provided most of the shade, about 90 are still alive.

Now the university has started on a 10-year reforestation program of planting 5000 young trees in accordance with a master plan that specifies the use of 37 species: 17 kinds called "primary trees ' for lining streets and quadrangles, and 20 others called "accessory trees". The later include 8 'accent ' varieties, 7 small flowering trees, and 5 evergreens.

The first known case of Dutch elm disease in Cook county was discovered in 1954. In 1955 there were 70, including six in the forest preserves. Since then our foresters have used all feasible means -- described in bulletin No. 569 -- to prevent the spread of this disease but the number of infected elms detected and destroyed each year multiplied until there were 7805 in 1961. Now, however, the number is decreasing.

We no longer propagate and plant elms because no species or variety is known to be immune to this fatal disease, although the Chinese and the Christine Buisman elms are much more resistant than others. In our landscaping and reforestation programs more than 40 other species are used, depending upon the location.

Where large fast-growing shade trees are needed, we plant balsam poplar, sycamore, honey locust, white ash, green ash, red maple, and silver maple. Trees that become large and long-lived but grow slowly are white oak, bur oak, hickory, walnut, sugar maple, and hackberry. Intermediate between those two groups are pin oak, Norway maple, horse chestnut, linden, and the tulip tree or yellow poplar. For city locations where smoke, fumes and poor soil are prevalent, the exotic ailanthus and ginkgo are recommended.

The University of Illinois program utilizes several species that do well in central and southern parts of the state but are risky here: sassafras, sour gum or tupelo, sweet gum, pecan, yellowwood and beech. Among the small flowering trees, in addition to the native hawthorns, crabapples and cherries, it includes the redbud, native magnolia and flowering dogwood which are risky here.

We plant trees for tomorrow.


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