INDICATOR SIGNIFICANCE OF NATIVE VEGETATION 271 



Mountains, points out differences in the density and composi- 

 tion of the living ground cover varying with the favorableness 

 or unfavorableness of the different lodgepole pine sites. The 

 vegetative succession occurring on the burns during the course 

 of the reestablishment of the original forest cover shows, in an 

 interesting way, the superseding of the xerophytically-inclined 

 vegetation by vegetation possessing more mesophytic tendencies, 

 until, as the site becomes more and more mesophytic, the orig- 

 inal forest cover is eventually established. The relative meso- 

 phytism of the site at each of the more or less distinct stages of 

 the succession is indicated by the native vegetation occurring 

 on the site at that particular time. It is true, however, that 

 the vegetation of any of the unstable stages of the succession 

 cannot be regarded as being indicative of the latent potentiality 

 of the site. The ultimate climax stage of the succession must 

 have been reached before much importance can be attached to 

 the indicator significance of the native vegetation in the deter- 

 mination of site, especially from the standpoint of the forester. 



Zon 7 in describing the forest types in which balsam fir (Abies 

 balsamea) occurs, states that sphagnum and other mosses are 

 the principal species which comprise the living ground cover of 

 the swamp type. Fern moss replaces sphagnum as the pre- 

 dominating ground cover of the flat type. Ferns and certain 

 flowering plants become the conspicuous herbaceous plants of 

 the hardwood slope type in which balsam fir is reported as 

 attaining its best individual development although the best 

 stand development occurs in the flat type. The descriptions of 

 the forest types are supported by lists which show the relative 

 proportion of the different species and the character of the 

 vegetation comprising the living ground cover of the swamp, 

 flat, and hardwood slope types. 



Hole and Singh 8 in studying the soil types and native vege- 

 tation of the sal forests in the vicinity of the Forest Research 



7 Zon, Raphael. Balsam Fir. U. S. Dept. of Agri. Bui. 55, pp. 4-7. 1914. 



8 Hole, R. S. and Singh, Puran. Oecology of Sal (Shorea ro'mste); Part I, 

 Soil composition, soil-moisture, soil-aeration. Indian Forest Records, Vol. 

 V, Part IV, pp. 13-14. 1914. 



