10 



sH than in th.- open. This has been conclusively proved by direct observa- 

 nfl Tho>,. uia.lr in I'avariii and Prussia show the following results : 



These data show that evaporation in the forest was only two-fifths of that 

 in the open country. 



The effect of this action is that of the water which falls on the ground in a 

 forest a considerably larger proportion is secured to the soil than in the open. 

 That wntci is available to be taken up by the roots, while any balance goes to 

 th.' -round water and helps to feed springs. Of considerable importance in this- 

 ivspect is the covering of forest soil. Dr. Ebenmayer's observations on thia 

 point, extending over five years, show the following results : 



Water evaporated from soil in the open 100 parts. 



Evaporation from forest soil, without leaf mould . . 47 " 



with full layer of leaf 

 mould 22 " 



In other words, forest soil without leaf mould evaporated less than half the 

 water in the open, while forest soil covered, with a good layer of humus evapo- 

 rated even less than one-fourth of that evaporated in the open. 



The result of these peculiarities is that, at any rate up to a certain elevation,, 

 the foiv-t soil retains, after allowing for evaporation, more water than open soil, 

 although some 23 per cent, of the rainfall are intercepted by the crowns of the 

 trees In order to illustrate this the following table, taken from Dr. Weber's 

 calculations, is inserted, as it shows the balance of rainfall over evaporation 

 according to elevation ; it is based upon Prussian observations : 



