FORESTRY SmVET 283 



cleared and is now nnder cnltivation. Brown silt loam is 

 an upland praiiie soil. It also was formerly partly, if not 

 entirely, covered with forests but it became occupied by 

 forests at a more recent time than did the timber soil and 

 the forests were of a diJierent type, as will be shown later. 

 Like the yellow-gray silt loam, the brown silt loam has been 

 mostly cleared and is under cultivation but remnants of 

 forest are found on it here and there. The slopes and 

 ravines are largely covered with yellow silt loam, which 

 like the yellow-giay silt loam is an uiilaud timber sod. In 

 some places this sod also extends back on to the upland 

 for some little distance from the slope. The most of this 

 soil is still covered with forests, as a residt of its being too 

 broken for agricultural purposes. The bottomlands are 

 occupied almost entirely by mixe<l loam, a bottomland 

 soil. All of this was formerly covered with forests and 

 while the larger areas have been cleared and are under 

 cultivation many of the smaller patches are still forested. 



Explanation of Map. 



Plant communities, including forests, are often classi- 

 lieil into three groups. Those that occupy the higher eleva- 

 tions where the supply of soil water is inade<iuate for many 

 kinds of plants are said to be xerophytic: those that in- 

 habit the lower places where the water supply is abundant 

 are calleil hydrophytic : and those that live in the inter- 

 mediate positions where the amount of soil water is 

 moderate but adei]uate are spoken of as mesophytic. On 

 the accompanying map. numbers from 2 to 29 are used to 

 designate forest associations that are more or less xero- 

 phytic : numbers from 30 to 39 indicate forests that are 

 moi*e or less mesophytic : and numbers from 40 to 59 refer 

 to forests more or less hydrophytic. The different tyes of 

 forests in these three groups will be described separately. 

 In all cases a whole number, as 34. imlicates a virgin 

 forest of good sized trees ; a fractional number with .1. as 

 in 34.1. refers to a second growth forest consisting, there- 

 fore, of small trees: a fractional number with .2, as 34.2, 

 means a very thin and open forest of good sized trees : and 

 finally a fractional number with .3. as 34.3. indicates a 

 forest area within which there are small irregular cleared 

 patches which may be under cultivation. A letter F on 

 the map indicates land which has been cleared but which 



