FORESTRY SURVEY 251 



and tliose of the bottom-land areas. While his report refers 

 principally to tlie forests of the southern part of the State, 

 his classification of forest types may in general be fol- 

 lowed. 



It is recognized that any classification whatever of for- 

 ests into a system of types or classes presents several diffi- 

 culties, not the least of which is the fact that such types 

 gradually merge into one another by gradations that are 

 often almost imperceptible. Still classes are necessary 

 for tlie mapping and intelligent discussion of any consid- 

 erable area of woodland. The following subdivisions are 

 offered as a provisional scheme arranged upon the prin- 

 ciple that it is best to have a small number of classes based 

 upon broad resemblances and differences. Variations in 

 these types, when of sufficient importance or when they 

 involve sufficiently large areas, may be noted in the dis- 

 cussions of the distribution of forests in the individual 

 townships. The application of the proposed classification 

 is at present to be limited to the requirements of a portion 

 of La Salle County, although it is confidently expected 

 that with slight modifications it will be equally service- 

 able for any portion of the State. 



I. Upland Types. 



These types include both the forests of hills and upland 

 plains although only tlie latter will be found within the 

 limits of La Salle County. Throughout the State various 

 species of oak dominate the uplands, the species differing 

 upon different soils and in different localities. L'sually 

 the soil of any particular type differs from neighboring- 

 forested or non-forested areas. Two main types may be 

 distinguished : 



1. Up] find oak forest. — The type of forest most extens- 

 ively developed in La Salle and also in many neighboring 

 counties is upon the uplands (mostly upon soil 1134 of the 

 Soil Report) and consists largely of various oaks, with 

 some admixture of hickory, so that it is often and quite 

 appropriately spoken of as the ''oak-hickory forest." In 

 anything like its original conditions it is a rich forest in 

 which either white (Qucrcus aJha) or red oak (Q. nihrn) 

 form from 50 to 80 per cent of the stands with varying 

 admixtures of bur oak (Q. niacrocarpa), shag-bark hick- 



