a) 



Time 



PNC 

 (Climax) 



Serai 



Riparian 



Assoc. 



B 



Riparian 



Assoc. 



C 



B-C2 



Riparian 



Assoc. 



D 



Comm. TypP^ ^omnTN ^omrr^N 



799 



Wet 



Riparian 

 Assoc. 



F 



7 — ^ 



' Comm. ' 

 Type 



Physical Environment (Site) 



Riparian 



Site Type 



F 



Dry 



b) 



— PNC — 

 (Association) 



Serai 

 (Common Type) . 



Range Site 

 (Site Type) 



Figure 1. Comparison ofTwoSuccessional Models, a) Illustration of classification 

 terminology as it relates to time and the physical environment (site) for riparian areas, 

 after Hansen (1989). b) Conceptual "cone" model of secondary successional plant 

 communities developed by Huschle and Hironaka, and Neiman, Jr. and Hironaka, 

 modified to illustrate terms as shown in "a" above, and those typically used within 

 range site descriptions. Depicted are two range sites, serai plant communities, and 

 range site specific soil imits. Note serai plant communities 4 and 5 can occur in two 

 sites having different potential natural communities (potential plant commtmities). 



