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UPLAND TYPE 



With the exception of two areas, one covering Jo Daviess County 

 and the other extending over Calhoun County and into Pike, the 

 uplands of northern Illinois are glaciated. There is a wide variety of 

 soils, both of residual and glacial origin. The topography is rolling 

 near the rivers, with level prairies between. The larger streams have 

 cut rather deep, steep-sided valleys, often exposing rock outcrops in 

 the form of precipitous cliffs. Some of the river bluffs are not so 

 abrupt, and the underlying rock is covered by deep loess deposits, 

 wind-driven from the bottoms, which form areas of rounded topog- 

 raphy and deep soils. These situations are usually stripped of the 

 original forest cover. 



The forests of these northern uplands are similar in many ways 

 to the oak-hickory type of the southern region, and along the river 

 bluffs they resemble to a certain extent the upland hill type. There 

 are, however, no post-oak flats, with the exception of a few areas in 

 northern Calhoun and southern Pike counties, and there are several 

 species peculiar to the northern part of the state. An increase in the 

 proportion of basswood, black walnut, cherry, and sugar maple is 

 the characteristic change from south to north; and as the extreme 

 north is reached, the presence of aspen, black birch, paper birch, and 

 even a sporadic occurrence of white pine, marks the overlapping of 

 more northern tree associations. Some species show a decided change 

 of habit toward the north, as the bur oak, which, while commoti on 

 the lower bottoms of the Illinois River, becomes a characteristic upland 

 tree in Jo Daviess County, and the red elm and cottonwood, which 

 are found on higher and drier ground than in the south. 



The timber of this region is almost entirely in the form of farm 

 woodlots, usually of small size. Although some few occur on the more 

 level land, the majority are found on the steeper valley sides. As a 

 rule, they have received more care than the southern woodlots, and 

 the resultant stands are better. This is not true, however, of the 

 woodlands along the bluffs and within easy reach of the Mississippi 

 River. These slopes have been cut over frequently to provide lime- 

 kilns with fuel, and now the growth is very scrubby. 



The predominating upland trees are black and white oaks in about 

 equal proportions. These two groups are represented on the better 

 and deeper soils by red and bur oak, respectively, while on the ordinary 

 wooded uplands, black, scarlet, and white oaks are most common. 

 A very small proportion of hickory is usually associated with the oaks. 

 Along the stream valleys the mixture is varied by white elm, sugar 

 maple, walnut, sycamore, hackberry, and honey locust. The river 



