25 



From southern Union county to the Wisconsin border, there is ap- 

 proximately 533,350 acres of bottomland on the Illinois side. This is 

 less than the area in bottomland on either the Wabash River or the Illi- 

 nois River. The soils are very variable, but usually approach clays in 

 the southern part and sands in the northern. The forested area, totaling 

 72,010 acres, or 16 per cent of the total bottomland, is about the same as 

 the forested area on the bottomlands of the Big Muddy River. Thirty- 

 seven per cent of this area is in timber of good saw-log size ; the average 

 yield per acre for this bottomland is 1,930 B. F. ; and more than half of 

 the forested area is in five counties. Jo Daviess, Carroll, and Whiteside 

 counties in the north have 21,538 acres of woods on the Mississippi bot- 

 tomland ; while at the southern extreme Union and Jackson counties have 

 21,351 acres of this bottomland forested. The forests of each of these 

 regions will be described as representing the conditions at the northern 

 and the southern extremes where the larger bodies of timber are found. 



In the southern part of the state, the bottomlands on the Illinois 

 side are from three to four miles wide. (See Map III.) Depres- 

 sions and sloughs of old river channels are frequent throughout, but 

 usually the elevation near the blufls is slightly less than nearer the river. 

 Also the deposition near the bluffs is very fine, and clays are common ; 

 while much of the recent deposit along the present channel is of a sandy 

 nature. The soils on this river plain are usually very fertile ; and, de- 

 spite the unfavorable factors, much of this land now forested will be de- 

 veloped, as virtually all is within organized drainage districts. 



At present, forests are found as rather continuous bodies averaging 

 less than a mile in width on the heavier soils near the blufi's ; as strips 

 bordering the sloughs throughout the bottomlands ; and as a belt along the 

 present river channel outside the levees. 



Based on -1.6 acres measured in Union county, the representation of 

 species in per cent is as follows : soft maple, 33 ; ash, 18 ; cottonwood, 

 14 ; elm, 12 ; hackberry, 10 ; pin oak, 3 ; red gum, 3 ; pecan, 2 ; river birch, 

 2 ; willow, 1 ; with occasional swamp white, bur, and lyre-leaved oaks. 



The stands inside the levees, usually restricted to poorly drained de- 

 pressions or heavy clay soils, are the remnants of the original bottomland 

 forests. In their virgin state these forests were heavy stands of ash, elm, 

 hackberry, soft maple, honey locust, various oaks, hickories, and gums, 

 but logging operations have left very little of the original forests. At 

 present these stands contain defective, or low-grade material, with valu- 

 able trees present in varying amounts. The best stands average as high 

 as 12,000 B. F. per acre. Logging is still conducted on a limited scale. 

 "Softwoods" suitable for fruit-containers' veneering grow verv rapidly 

 on these bottoms, and this region is the logical source of supply of this 

 material for the adjacent fruit and truck gardening region. Pecan, being 

 native to this region, is also encouraged and in places on these flood-plains 

 the regular bottomland association is enriched by beech. 



