204 



P.J. Webber et al. 



EXPOSED SITES 



High 



Wind 



Litter 

 blown 

 away 



Cooler 



temperatures 



m actrve 



season 



Reduced 



nutrients 



Reduced 



growth 



Higher plant 

 temperature 

 near surface 



High vapor 



pressure deficit 



possible 



High leaf 

 resistance 



Low 

 photosynthesis 



Longer leaf 

 duration 



!|M 



Low 



growth 



form 



Low 



winter 



precipitation 



Low 



summer 



precipitation 



Low snow 

 cover 



Winter 

 exposure 



Increased 



abrasion 



loss 



Low soil 

 water 



Surface 

 i^xposed 



early 



Photosynthesis 



possible 



while roots 



are frozen 



Protected 



buds 



Periodic 



summer 

 drought 



Photosynthesis 



possible 

 before growth 



Enzymes 

 stored in 



leaves 



Evergreen 

 leaves 



Rig'd 

 leaves 



Deep 



roots 



1 



Evergreen shrubs and caespitose graminoids 



I 



Luzula heaths and Salix heaths 



FIGURE 6-8. Diagrammatic relationships between major environmental 

 factors and plant characteristics. The diagram consists of two complexes: 

 those for exposed sites which lead to plant characteristics to be found in 

 evergreen shrubs and caespitose graminoids of Luzula and Salix heaths 



