igoS] TRANSEAU 



APORA 



221 



more or less stable. 



The yaporimeter was placed on the border 



between these two areas. 



Growing near the instrument were the following plants in very 

 open association: Polytrichum sp. ? Androgopon sco partus, Deschamp- 

 sia flexuosa, Comptonia peregrina,. lonactis lincarijoUa, Baptisia 

 tinctoria, Epigaea repens, and Vaccinium pennsylvanicum. 



.' 



im 



•<*, 



Fig. 4- — Station 4; partially invaded gravel sKde. 



Amt. evaporation, Station 3 . . 

 Amt. evaporation, standard . . 



aporation 



June 28-July I 



■ 34.3 

 . 99.1% 



Jiily 1-8 

 140-3''' 



92.6% 



Julv 8-14 



145-6^" 



131-5 



110.7% 



Total (16 days) 



319 9« 

 317 3 



The bare gravel slide therefore shows an evaporation approxi- 

 niating that of the standard* As shown by s}Tichronous temperature 

 records, the surface on sunshiny days rises 20^ above that of the 

 garden, but the corresponding increase in evaporation seems to be 

 largely compensated by the somewhat lower night rate. This gravel 

 slide station represents the pioneer stage in the reforestation of a 



