Ross: The Dunesland Heritage of Illinois 5 



stretches to the Atlantic Ocean; westward it is replaced in a few 

 hundred miles by the great central grasslands, fig. 4. Mature stands 

 of the temperate deciduous forest consist of various mixtures of a 

 wide variety of hardwood trees including different kinds of oak and 

 hickory, hard maple, beech, and linden. When areas of this mature 

 forest are disturbed in such a way that trees are no longer present, 

 other natural plant communities grow up in their place. In most 

 Illinois areas from which forest has been cleared, the land plowed 

 and cultivated, and then left idle, the bare earth is colonized first by 

 some of the annual grasses and other herbs, later by perennial plants 





IS 



TUNDRA OR ICE 

 HUMID CONIFEROUS FOREST 

 BOREAL CONIFEROUS FOREST 

 TEMPERATE DECIDUOUS FOREST 

 MONTANE CONIFEROUS BIOMES 



^^ CHAPARRAL AND XERIC FORESTS 



1 1 GRASSLAND BIOMES 



I I SEMIDESERT BIOMES 



(ZZI DESERT 



^^ SUBTROPICAL HAMMOCK-EVERGLADES 



Fig. 4. — Principal oreos of ferresfrial biological zones or biomes of North America. 



