350 



present climatic conditions, the prairie of this region will ultimately 

 give place to the deciduous forest. 



In dealing with the conifer forest province it must be kept ui 

 mind that the area is several (130) kilometers south of the southern 

 limii'. of the province in eastern Wisconsin, and virtually no invasion 

 by if into other provinces could be expected. The question is whether 

 or not it can hold its own. In the case of the prairie this question 

 is usually decided in the affirmative, as the prairie can not exist m 

 the dense shade of the conifers. It spreads into the pines only when 

 some of their number die. Then it takes possession of the open spaces 

 and prevents reproduction of the ]:)ines, so that with the dying of the 

 old trees the prairie is left supreme. (Fig. 2, PI. LVI.) 



Seedlings of the oak Qucrcus vclutina, are present almost 

 throughout the area of the pines, with the exception of the very 

 densest parts. While usually only the oaks in the open places de- 

 velop, the continual presence of seedling oaks under the pines means 

 that whenever a pine dies, in a short time its place is occupied by a 

 number of oak trees, under whose shade the seedling pines — few in 

 number at best — can not develop. It is therefore clearly evident that 

 in this region the remaining representatives of the conifer forest 

 province will ultimately be replaced by trees, representative of the 

 deciduous forest province. 



These same general statements, slightly modified, hold true for the 

 heath association, a member of the conifer forest province. 

 The typical heath plants are somewhat more lenient in their 

 ecological demands than the coniferous trees, which signifies, 

 how'ever, only that a much greater length of time will be nec- 

 essary to effect their elimination froni the region. As long 

 as the prairie growth is fairly open, the heath and prairie 

 plants thrive together, but a dense prairie growth is very efficient in 

 choking out the heath. Heath plants are only fairly tolerant of shade; 

 but as long as the open black oak woods prevail, the heath can read- 

 ily persist in the open places. Greater shading eliminates bearberry 

 (Arctostaphylos), but Juniperits horizontalis and especially /. com- 

 viunis depressa can exist even in the much denser shading of a bur 

 oak {Querciis macrocarpa) w^oods. Here, however, they are etio- 

 lated in response to the diminution of light, and show- the other char- 

 acteristic modifications induced by shade, namely, broader, flatter 

 leaves which spread more, making a looser and w'eaker growth. 



The deciduous forest — now occupying nearly half of the Beach 

 area — is the natural climatic floral province to be expected in this 

 region w-ith the present conditions of climate. In all natural sue- 



