28 



A Study of the Vegetation of 



this station was intermediate in xerophytism, as expressed by the 

 evaporating power of the air, between the two stations in the 

 pines. A second station in the shrub on the north slope of the 

 butte and near the western end was maintained in a dense growth 



JLY 



A'(/G(J&T 



f/b/7 



oes 



'* micftum 



-/ ^ 

 / / N . 





V 



LL 





\ 











FIG. 6. Evaporation rates in the various plant communities on Kamiak 

 Mountain, and in the Pine consocies (graph 4) at Viola, Idaho. 



of Opulaster-Ceanothus chaparral. The evaporation rates, not 

 shown in the chart, were much lower, often being less than those 

 in the fir-tamarack forest. In fact, it is not difficult to find situa- 

 tions in which shrubby growth is so dense as to greatly retard 

 evaporation and reduce the light to a point where pine seedlings 

 can not grow. 



28 



