348 



General Conclusions 



Consideration of the foregoing" data makes evident the sticces- 

 sional relations of the three floral provinces represented in the Beach 

 area. And what holds good for this area is applicable to north- 

 eastern Illinois and southeastern Wisconsin in general, as might nat- 

 urally be expected. Over the greater part of this general region 

 there is a greater extent of prairie than of forest, but in the Beach 

 area, forests occupy about half the ground. The larger part of the 

 forest is the deciduous forest of the southeastern center of dispersal. 



Successions clearly show that there have been times in the past 

 when each one of these provinces was more widely extended than 

 is now the case. This is particularly true of the prairie and the coni- 

 fer forest, for they are gradually being reduced in extent through 

 natural causes which at the same time favor the increase of the de- 

 ciduous forest. Aside from wave action the factors that tend toward 

 the destruction of the deciduous forest are all connected with the in- 

 roads of man. 



Before going further into detail, a recapitulation of the pertinent 

 characteristics of the vegetation of the different floral provinces is in 

 order. 



Prairie Province. — The vegetation is less than two meters, usually 

 about one meter, in bight, consisting of grasses and herbs usually as- 

 sembled very closely together, often forming sod. The plants will 

 stand a considerable variation in the moisture content of the soil but 

 require virtually the maximum amount of light. 



Deciduous Forest Province. — The dominant plants are deciduous 

 trees, in the more xerophytic associations, such as are represented in 

 this region, rather openly assembled, giving all variation in shade, 

 usually with little or no sod. The ground vegetation is open, and 

 often consists of a number of plants whose showy flowers constitute 

 the seasonal aspects. The seedlings are rather intolerant of shade, 

 but otherwise develop very readily. Once established on this sandy 

 soil, associations of this province are usually permanent. 



Northeastern Conifer Forest Promnce. — The plants are ever- 

 green trees or prostrate evergreen shrubs, growing in sandy soil in 

 more or less closed assemblages. The denser assemblages of trees 

 cast so much shade that all undergrowth is prohibited and the ground 

 is carpeted with pine needles. Where the assemblages are more open, 

 there are numerous herbaceous plants. With the exception of a very 

 few local stations, the pines of this region are not reproducing them- 

 selves. On the other hand, the heath plants reproduce readily, by 



