24 A Study of the Vegetation of 
Fig. 4 shows the comparative average daily evaporation rates 
during 1913 in the three communities, respectively. These data 
— 
i es A SS BS ee a 
Fic. 4. Average daily evaporation rates in the Agropyron, Festuca, and 
Pinus communities during 1913. 
are averages of six stations located in the several communities. 
The water content of the soils at the preceding stations at Col- 
fax is indicated in Fig. 5. A glance shows that the soils covered 
by the Agropyron consociation had at all times the lowest avail- 
able water content. Those of Pinus and Festuca communities 
are approximately the same, and indeed this condition has been 
found to exist elsewhere in several similar situations. Isolated 
determinations at the same stations at various intervals during 
the following season showed a similar water content relationship. 
psy | || uve | | ety | || augue IIs | 
LTT tested {I 
SAS eee 
c ie SCE HHS 
Fic. 5. Graphs showing the march of soil water to a depth of Io inches 
in various plant communities at Colfax, Washington. 
24 
