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UPLAND PLAIN TYPE 



The region covered by the lower Illinois glaciation lies north of 

 the Ozark Hills and west of the Mississippi bluff land, and is charac- 

 terized by distinct forest types. The topography is smooth, with little 

 or no rock outcrop, and varies from flat plains to undulating or gently 

 rolling country cut by the shallow valleys of small streams. The soils 

 are inclined to be sour and to be inferior in fertility. 



The forest is characterized by the preponderance of oaks. It may 

 be divided into two subordinate types which depend on the soil and 

 topography for their distribution, but which are so intermixed as to 

 preclude the possibility of separating them on the map. Each of these 

 has within itself many minor variations in composition, dependent on 

 the variations in local conditions. 



Oak-Hickory Type. — The oak-hickory type is composed principally 

 of the black oaks, white oaks, and hickories. It is found on well- 

 drained, undulating country having a yellow-gray or yellow silt loam 

 soil. The forests of this type are generally in the form of small 

 woodlots, and are held as sources of wood supply for individual farms. 

 They are largely situated on broken land along stream valleys least 

 suited to agriculture. The conditions of density and form are variable. 

 Sometimes the forest takes the form of an open grove used as pasture 

 for cattle or hogs, and sometimes that of a dense woodland with 

 underbrush and a good amount of young growth. 



Black oaks generally exceed the white oaks in volume, but in second- 

 growth stands the latter not uncommonly predominate because of their 

 excellent reproduction. The stands are for the most part second- 

 growth, of seedling or sprout origin, often with scattered veterans of 

 the virgin stand. Virgin stands of even small extent are rare, and 

 when present are along the small stream valleys or on slopes too steep 

 for agriculture. 



The rate of growth of these forests is comparatively good, though 

 slower than on the bottoms. Reproduction is also excellent, except 

 where fire or heavy grazing has prevailed. The poorer sites generally 

 have a great deal of hickory among the young growth, but on the 

 better soils and under good conditions the oaks predominate. The 

 large proportion of young white oak, a condition unusual in so many 

 other hardwood forests, is very encouraging. The young trees are 

 generally in small groups, in openings made by former cuttings. 



Fire and grazing have done a great deal of damage. Reproduction 

 is rendered impossible, young trees are seriously injured or killed, 

 and the humus content of the soil is often very much reduced. Insects, 

 while present in fairly large numbers, have not infested the thrifty 

 vigorous trees which have not been weakened by fire. About seventy- 



