28 



The Mississippi bottomland between the northern and southern ex- 

 tremes has been developed. Forests are found rather generally on the 

 low islands, outside the levees, and hold a very restricted area elsewhere. 

 Also, river development, notably at Keokuk, has raised water levels over 

 considerable areas, thus drowning out the forests outside the levees. In 

 certain regions (Carroll and Henderson counties) sands are found on the 

 flood-plain. Here the forest growth is altogether different from the 

 usual bottomland association. It is described under the scrub oak type. 

 In many instances the stands on the islands are cut regularly for cord- 

 wood from which charcoal for gunpowder is derived. A pulp manu- 

 facturing company has purchased several islands and is developing plan- 

 tations of Cottonwood and maple. 



The association is similar to that in the extreme northern area, the 

 soils are usually fertile, and growth rates are excellent. 



The Illinois River System 



The bottomlands of the Illinois River are very definitely bounded on 

 each side by bluffs from four to ten miles apart. The soils are light, 

 pure sands being common. Formerly this river valley contained many 

 large areas of shallow lakes and sloughs where reeds and willows pre- 

 vailed. Drainage projects have reclaimed most of this valley with the 

 exceptions of the lower twelve miles, of the region near the junction of 

 the Sangamon, and of the region of the Big Bend at Hennepin. These 

 areas have some 3,000, 4,000, and 16,000 acres respectively of bottom- 

 land forested, but 77.4 per cent of the entire valley is cleared. The de- 

 velopment of levees, in most places, has confined the river within a nar- 

 row channel, while the Chicago Sanitary Canal has increased the volume 

 of water. Consequently, those forests outside the levees or in undrained 

 areas have been killed by excess flooding, and throughout the lower part 

 of the valley forest conditions have been changed by changing water- 

 levels. 



These forests have been culled heavily for saw-timber until there 

 remains but 13,113 acres, or 9.8 per cent, in good saw-timber on a total 

 of 123,651 acres forested. Even saplings and immature timbers are har- 

 vested for pulpwood and cordwood. Based upon samples aggregating 

 4.78 acres taken in two counties, the representation in per cents by species 

 is as follows : soft maple, 55 ; cottonwood, 18 ; elm, 11 ; pin oak, 4.5 ; 

 pecan, 3.5 ; ash, 3 ; willow, 3 ; river birch, 2 ; with infrequent bur oak, 

 hickory, sycamore, black walnut, and honey locust. Thus soft maple, 

 cottonwood, and elm make up 84 per cent of the stands ; and oak-hickory 

 comprise less than 5 per cent of the stands. 



With the adjustment of the average water-mark to new and higher 

 levels, there has followed a readjustment of forest associations. The 

 cottonwood, maple, and elm have at first controlled many of the new 

 sites. Cottonwood, on light soils such as prevail over much of these 

 bottomlands, outstrips all competitors in growth, and is the most profitable 

 forest tree for such land. 



