APPLIED ECOLOGY 359 



most promising approach to recognition of site quality. Once 

 these two factors are known for the soils of an area, they can be 

 recorded like a soils map, which then becomes a map of site index 

 to be interpreted for management purposes. 



Innumerable indicators, other than site indicators, are used in 

 forestry. Relicts are particularly useful, and successional indi- 

 cators are applied regularly. Special instances have been suggested 

 elsewhere. It is appropriate to emphasize that indicator applica- 

 tions are invariably successful when the ecology of the region and 

 the species is known. 



HUMAN ECOLOGY 



Perhaps this final section seems out of place in a textbook 

 intended as an introduction to plant ecology. Undoubtedly, its 

 subject should not be looked upon as an application of ecology in 

 the sense of the preceding paragraphs of this chapter. The intent 

 is to emphasize that all organisms are related to their environments 

 and, consequently, to each other and that, therefore, they will be 

 best undestood when studied from an ecological point of view. 



Considering the youthfulness of the science of ecology, it has 

 contributed much to our understanding of plants and animals at 

 the same time that its methods have won approval and even adop- 

 tion in other fields to the benefit of all. Although we still have 

 plant ecologists and animal ecologists, and probably will continue 

 to have such specialists, there has been a steady increase in the 

 appreciation of interrelationships among plants and animals. 61 



Furthermore, there is a growing realization that man is like- 

 wise subject to ecological laws. This is completely reasonable 

 since man, like other organisms, is basically dependent upon his 

 environment and is likewise a factor in that environment. With 

 man's increasing dominance, it is desirable that these relationships 

 be better understood. How better can one approach that under- 

 standing than through studies of the structure of the communities 

 in which man dominates, their origins and successional develop- 

 ment, and the controlling factors involved. This is human ecology. 



This is not a new idea, but it has not been widely recognized 

 or accepted. There is much evidence that it is gaining recognition. 

 There is an increasing appreciation of the concepts and values of 

 ecology among the public in general as evidenced by the not 



