34 A Study of the Vegetation of 
the butte-prairie and yellow pine communities. These data show 
a marked relationship between the evaporating power of the air 
and the stage of succession. Fuller (4, 5) has determined a simi- 
lar relationship for the plant consocies which culminate in the 
beech-maple climax forest. It is interesting to note in this con- 
nection that the evaporating power of the air in the Thuja climax 
forest is only slightly greater (0.5 c.c. daily in 1913) than that 
of the beech-maple forest climax of the East. 
In order to further check these results, evaporation readings 
were taken again in the cedars and fir-tamarack on Cedar Moun- 
tain during 1914. To this series of stations was added one in a 
very open yellow pine consocies on a wind-swept western slope. 
The results are given in Table IV. 
TABLE IV 
SHOWING THE AVERAGE Dairy EvaporaATION RATES IN THE PINE, FiIrR- 
TAMARACK, AND CEDAR COMMUNITIES DURING THE SUMMER OF IQI4 
July 3-11 | July 11-18 | July 18-25 | 25-Aug.1 | Aug.1-7 | Aug, 7-14 
PINES = ae eae sei LO Cc. 24 37 35 40 34 
Fir-tamarack...| 13 ¢.c. 13 20 20 23 22 
Cedatsix Jin ucisns 10 c.c. m0) 14 16 18 7 
A record of the water content of the soils at the stations in the 
cedars and fir-tamarack on Cedar Mountain was kept from June 
14 to September 17, 1913. During 1914 this was repeated for a 
period, and to this a record of the soil moisture at the station in 
the pine community was added. The results are shown graph- 
ically in Fig. 10. A glance shows that the cedars occupy by far 
the most mesophytic habitat. The high wilting coefficient indi- 
cates at once a fine textured soil with considerable organic matter. 
A mechanical soil analysis (Table II) reveals just such charac- 
teristics. This is in marked contrast to the coarse sandy loam of 
the station in the pine. Likewise, a chemical analysis (Table III) 
shows 13 per cent. of volatile and organic matter in soils of the 
cedar community, and 8 per cent. in those occupied by the firs 
and tamaracks. The water holding capacity of these soils is re- 
markably high. It was found to be over 100 per cent. of their 
34 
