97 



EVAPORATION IN WOODS IN PER CENT. OF EVAPORATION IN THE OPEN. 



The difference in instruments used by Dr. Ebermayer or their exposure 

 is prohalily tlie cause of tlie relatively slii^ht differences in the results. 

 One of the most striking features of the table is the retarding effect that 

 forest litter is seen to have upon the soil beneath. About seven-eighths 

 lit the loss of water by evaporation is cut off ])y the forest and litter. The 

 stations of Prussia allow the following average for evaporation, the amount 

 evaporated in the open field being called 100 : 



Tnder beech growth. . 

 I'nder spruce growth . . 

 I'nder pine growth . . 

 From cultivated field 



Olher data from I'russia are also given which show thai: greatLn- 

 amounts are lost by exaprration in the open than in the forest. Investi- 

 gations by Shimek ( :J4 ) in western and northwestern Iowa show that 

 evaporation is much greater on prairie surfaces than in adjacent forests. 

 It must therefore be admitted that wastefulness by evaporation from the 

 ground is reduced by forest cover. 



[7—29034] 



