NATURE OF THE COMMUNITY 



23 



other less but will most certainly not be of equal importance in the 

 community. A tall-growing species outgrows a potentially short 

 one under the same conditions. If the latter then survives, it does 

 so because its light requirements are not great. Thus the one tends 

 to occupy a higher level than the other and to form an overstory. 

 In this way stratification may develop in a stand in which the 

 upper stratum of plants usually includes the controlling and char- 

 acteristic species for the community. These are termed the dom- 

 inant individuals. If they are removed for any reason, as by selec- 

 tive cutting or disease, dominance is usually assumed by other 

 species, and the character of the community is changed completely. 

 This is not true when lesser species in subordinate strata are re- 

 moved, for, with the dominants intact, the same type of commu- 

 nity can regenerate itself. 



Stratification may likewise be seen among the shrubs and herbs 

 beneath the trees, since some may be tall and some low. The lowest 



Fig. 3. A stand of moss (Hypnum crista-castrensis) on the forest floor in 

 northern Wisconsin. Although this species is a dependent within the forest 

 community, it forms a stand nevertheless— Photo by L. E. Anderson. 



