226 THE STUDY OF PLANT COMMUNITIES * Chapter IX 



in this sense be indicated by referring to climax associations or 

 major associations, but this has not been generally accepted as yet. 

 An attempt was made to standardize the use of the term at a recent 

 International Botanical Congress, but, even so, the rulings have not 

 been completely accepted. For a summary of some of the diverse 

 points of view and some applications of the term, reference should 

 be made to Conard's 67 discussion of plant associations and its ap- 

 pended bibliography. 



Types of Climax.— In a climatic area, all succession is in the di- 

 rection of a community that can maintain itself permanently, and 

 there is only one such community for the region as a whole. How- 

 ever, succession is often halted temporarily in almost any stage of 

 its progress, and sometimes is halted almost permanently in late 

 stages. Diseases, fire, insects, or man may produce conditions that 

 prevent completion of succession and hold it indefinitely at some 

 stage preceding the climax. Edaphic or physiographic conditions 

 may be such that succession cannot proceed to completion. Al- 

 though such communities may appear to be as stable and perma- 

 nent as climax, they cannot be considered as such because they are 

 not controlled by climate. 



This is the monoclimax hypothesis. In contrast is the polyclimax 

 view, which recognizes edaphic, physiographic, and pyric cli- 

 maxes within a climatic area. The conflict between the two views 

 lies in the interpretation of the concept of climax. Actually, the 

 same communities are recognized by both but under different 

 terminology. Since the basic concept of climax implies one ultimate 

 community controlled by climate, the monoclimax view is con- 

 sistent with the meaning of the term. When used in conjunction 

 with a few precise terms, 60 which are discussed below, it is ade- 

 quate for explaining all climax variations. 



Subclimax.— When, in any succession, a stage immediately pre- 

 ceding the climax is long-persisting, for any reason, it can be called 

 subclimax. It may be the result simply of extremely slow devel- 

 opment to climax, or of any disturbance, such as fire, that holds 

 succession almost indefinitely in its subfinal stage. In the eastern 

 United State, most pine forests are subclimax to hardwood climax 

 because of the relatively slow elimination of pine in the progression 

 toward hardwood dominance. In the coastal plain, subclimax pine 



