CONSOCIATIONS 



195 



tion, therefore, as there are dominant species. Theoretically there 

 is no reason why there should not be some associations with but one 

 dominant species. In such a case the single consociation would be 

 coextensive with the entire association. Practically, however, all 

 associations have several dominants. In many cases the dominant 

 species are mixed throughout the association and therefore the con- 

 sociations are mixed and are coextensive with the association as well 



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Fig. 84.— Yellow pine consociation in a yellow pine-douglas fir association, 

 (Photograph by A. G. Varela. Courtesy of H. L. Shantz and the U. S. Depart- 

 ment of Agriculture.) 



as with one another. In all of these cases, however, there is no 

 practical reason for recognizing consociations at all and it is probably 

 better, on the whole, not to do so. The recognition of consociations 

 becomes of value, however, in case a part of an association is domi- 

 nated by a single species to the exclusion of other dominants. For 

 example, in an upland oak-hickory association in which the dominant 

 species are white oak, black oak, and shag-bark hickory, we may 

 find a portion of the community in which the white oak is the only 

 dominant that is present, or the only one that is present in sufficient 

 numbers to have any real share in the control of the community, 

 and it becomes convenient in such a case to speak of this morpho- 

 logical part of the association as a white oak consociation. 



