Site Progression 



Stream, Aquatic 



B4orB6 



stream type 



Upland Bottom 

 Assoc, w/ B, C, 

 or F stream ^pe 



Frequently Rooded 



Wet Meadow 

 Assoc, w/ B6 stream 



Semi-Wet Meadow 

 Assoc, w/ B, C, 

 or F stream type 



Figure 2. Concept of Site Progression. The boxes represented as "states" may include a 

 number of different site types and may be found associated with stream types (i.e., B4, 

 B6, etc.) as described by Rosgen (1985). 



other self-perpetuating species. The decadent cottonwood stand is now an early successional 

 stage to a different potential natural community. Vegetation succession may or may not be 

 allowed to proceed long enough to reach that new potential, depending on stream dynamics 

 and hydrology in relation to the valley bottom morphology. 



Since riparian systems are dynamic, some may never be able to attain a climax community, or 

 at least not attain it without long term evolution of existing valley bottom morphology. A 

 stream flood plain developing within the walls of a past incisement provides such an ex- 

 ample. The soil-water-plant relationships within the developing flood plain may provide the 

 same wet meadowAneadow complex of site potentials as found elsewhere. The stream 

 channel may be aggrading at approximately the same rate as the adjacent flood plain. Site 

 progression, in this case, is actually increasing the aerial extent of the riparian vegetation (and 

 associated ground water) as the system aggrades. The system is in an excellent functional 



