The original forests have been reduced in area 80.22 per cent and the 

 estimated yields 94.64 per cent. 



Present Forests of Illinois 



The field work of the survey of the present woodlands in Illinois 

 was begun during the summer of 1921 and finished in 1924. Approxi- 

 mately 66 per cent of the state was systematically surveyed to determine 

 the location, area covered, and condition of the forested areas. The 34 

 per cent of unsurveyed acreage is in the prairie counties where the small- 

 est amount of woodland exists. 



The methods of making the survey were as follows : 

 Forested areas were drawn on a base map of the region. In the very 

 rough sections where no roads gave access to the country, the ground was 

 covered on foot or horseback ; over much of the state such mapping was 

 done from an automobile. Distances to the wood-lot were estimated. 

 Usually the sections are subdivided into forties by fencing, and this serves 

 as a useful check. The estimated yield per acre of the area under obser- 

 vation was entered. As a check occasional samples were tallied and 

 yields computed. The field data were worked up in the office to show the 

 total forested areas and yields by counties. The tabulation of this in- 

 formation is given on pages 58 to 63. The maps III to VI reproduce, 

 on a scale one fourth as great, nine of a series of twenty-seven maps 

 made in the working-up of the field data. 



general COMrARISON OF BOTTOMLAND AND UPLAND FORESTS 



In a description of the present forests of Illinois, several natural 

 divisions suggest themselves. The two general divisions — bottomlands 

 and uplands — have forests of quite dissimilar composition. 



The bottomland forests of the state originally bore a higher yield 

 per acre and a greater variety of species than did the uplands. The area 

 of bottomland estimated to have been covered by these original forests 

 was 2,898,945 acres, virtually all of the bottomlands of the state. They 

 probably contained 25,725,724,000 B. F. of lumber, an average of 8,875 

 B. F. per acre for this large area. Small areas having more than 25,000 

 B. F. of hardwoods to the acre still remain. The present bottomland 

 forests cover an area of 739,508 acres, and have an estimated yield of 

 1,029,937,000 B. F. ; an average of 1,393 B. F. per acre. Efficient log- 

 ging can not ordinarily be carried on in stands of less than 2,000 B. F. to 

 the acre. Eliminating all stands of saplings — fully stocked immature 

 stands yet too small to produce lumber profitably — and those stands which 

 have been culled until only occasional trees are of sawlog size, a state-wide 

 comparison of desirable sawlog stands between uplands and bottomlands 

 is about as follows : 8.9 per cent of the upland stands and 22.69 per cent 

 of the bottomland stands yield 2,000 B. F. or better to the acre. Al- 

 though the bottomlands occupy but one-quarter of the total forested area 

 of the state, yet they contain almost as many acres of merchantable sawlog 



