Nov., 1918] Recovery of Vegetation at Kodiak 



21 



standard type, where humidity was at a minimum and evapora- 

 tion high (see below), it is evident that there was small danger 

 of seedlings suffering from drought in the field. 



The evaporation data were taken by non-absorbing cylin- 

 drical atmometers furnished by the Plant World Company. 

 One was located in an open school yard beside the other 

 instruments, a second in a dense growth of young spruce 

 trees near Vegetation Station 11, a third in an open glade 

 formerly occupied by a small bog (Vegetation Station 12), a 

 fourth on a steep mountain side in the Calamagrostis-Alnus 

 association at an altitude of two hundred and fifty feet, (Vegeta- 

 tion Station 28), and the fifth on the summit of Pillar Mountain, 

 a bare wind-swept situation at an altitude of twelve hundred 

 feet (Vegetation Station 17, see page 26). The average daily 

 evaporation rates from these instruments, corrected by the 

 coefficient supplied with the cups to reduce it to that of the 

 standard instrument, is given in Table III. The table gives 

 both the absolute rates and the ratio of evaporation in the 

 different habitats. 



TABLE III. EVAPORATION DATA AT KODIAK. 



Evaporation from white cylindrical porous cup atmometers reduced to 



standard values. 



The data shown in Table III need no comment, except 

 in the case of the mountain summit. This station was bathed 

 in thick fog for many days when the lowland was clear. As 

 there were usually high winds on such days, the evaporation 

 on the lowland was often considerable, when moisture was 

 condensing around the mountain top. Since, therefore, the 

 period of evaporation on the summit was much shorter, the 

 comparative rate, when evaporation occurred at all, must have 

 been considerably greater than is indicated by the results, 

 notwithstanding the fact that this station had a much higher 

 rate than the base station. This is probably of great importance 



