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THE LIFE OF THE DUNESLAND 
Dr. Herbert H. Ross 
Illinois Natural History Survey 
ILLINOIS LIES ALONG the western edge of the temperate deciduous 
forest. To the east this forest stretches to the Atlantic Ocean, but to the 
west it is replaced in a few hundred miles by the great central American 
grasslands. Mature stands of this forest consist of various mixtures of 
hardwood deciduous trees, including different kinds of oak, hickory, hard 
maple, beech, and linden. When areas of the forest are disturbed, other 
sets of ecological communities grow up instead. The bare earth is colonized 
first by some of the annual grasses and herbs, later by perennial plants 
such as the bluestem grasses and blazing star, then with shrubs and small 
trees such as the red haws, and finally, after many years, the deciduous 
hardwood trees grow over the colonizing communities and the mature 
forest is re-established. The Illinois Dunesland area, which is of such 
great interest to us, represents one of these colonizing communities. It 
is, however, no ordinary set. 
In an ordinary upland where forest has been cleared, the land plowed 
and cultivated and then left idle, colonizing communities such as the ones 
outlined above do occur, but they lack many components found in the 
Dunesland. Plant communities in the Illinois Dunes are growing on sand 
and gravel bars which have never been covered with forest and which 
have peculiar conditions of soil and subsurface water, conditions favoring 
many plants unable to thrive in different surroundings. 
Usually we do not feel that we understand a situation until we know 
its history. We must know how an environment started, and the process by 
which it came to be what it is. A knowledge of such history helps us to 
understand ecological communities. The intriguing dunes areas along the 
Illinois shore of Lake Michigan exemplify this principle The history of the 
Dunesland goes back to the origin and evolution of the temperate deciduous 
forest and its satellite communities, and to the forces that produced the 
sand and gravel bars and swales found in the Dunesland. 
First, the history of the forest: Exactly when the temperate deciduous 
forest as we know it came into existence is difficult to determine. Some 
elements are present in the fossil record of Cretaceous times, about 120 
million years ago. Working with fossil forms, the paleobotanist, Dr. Pierce, 
found in this period the Minnesota forests contained pines, lindens, witch 
hazels, and other trees like those of the present. Whether these ancient 
forests were chiefly coniferous, with a scattering of deciduous trees, we 
do not know. 
At a much later time, in the Oligocene period about 50 million years 
ago, there is excellent fossil evidence showing that temperate deciduous 
forests existed which may have looked like those of today. They contained 
similar species of oak, hickory, linden, beech, sycamore, and many other 
trees. The Oligocene trees differed in an important way from those of the 
present. They stretched in an unbroken band from the Atlantic Ocean, 
across North America, through southern Alaska, and across Eurasia to 
