OSMOTIC PRESSURE AS AN INDEX OF HABITAT 1013 



In applying their method to field conditions McCool and Millar found 

 "that the freezing-point lowerings of the leaves and roots of the same 

 crop growing on different soil classes of high water content do not vary- 

 appreciably." This makes the method the more valuable as an index 

 of soil moisture, in that it eliminates the factor of variation in soil 

 fertility. 



These investigations on osmotic pressure, as indicated by freezing- 

 point depression, have a direct bearing on forest research, in that they 

 reveal the existence of an index of habitat which may be of great value 

 in silvical studies. 



