286 CLARENCE F. KORSTIAN 



In studying the indicator significance of the native vegetation 

 it is necessary to go directly to the individual species instead 

 of attempting to stop at the association, society, or community, 

 since the vegetation as an integral is composed of individual 

 species and in intergrating the vegetation it must be remembered 

 that the behavior of the vegetation is a resultant function of 

 the behavior of tjie component species. It is impossible in arid 

 and semi-arid regions having many diverse biological growth 

 forms, to select a group of plants which may be regarded as 

 associates without finding that the association may have been 

 disorganized elsewhere and that some of the individuals enter 

 into other associations as component parts. 



It is freely admitted that the best ultimate criterion of site 

 quality is the increment of the aborescent species concerned, as 

 judged by the measurement of an approximately fully stocked 

 stand. In cases where the increment data are rather meager 

 or are entirely lacking the native vegetation present should 

 serve as a valuable criterion of site for those species addicted to 

 growing in rather open, park-like stands, such as western yellow 

 pine. In this connection it should be remembered that a plant 

 rarely requires more than a few years at most to reach the adult 

 form, while the forest often requires a century or even two in 

 which to reach maturity. The writer believes that the native 

 vegetation found on deforested areas may be considered as a 

 criterion of the latent potentialities of the site for forest produc- 

 tion provided the vegetation has not been too severely and too 

 recently disturbed and that the more important phases of the 

 successional series are properly understood. 



Studies are under way at the Utah Forest Experiment Station 

 in central Utah, the object of which is to determine the feasi- 

 bility of using native plants as indicators of suitable forest plant- 

 ing sites. By making detailed studies of the root systems and 

 subterranean moisture-absorbing surfaces of the typical her- 

 baceous, shrubby and arborescent species of each important 

 association, the value of the native vegetation as indicators of 

 those climatic and edaphic conditions under which the important 

 coniferous species may be planted successfully should be deter- 



