FOREST INFLUENCES. 27 



weather bureau do not show that there is any connection 

 between the two or that there has been any apparent 

 change in the general climate or amount of rainfall due to 

 the removal of our forests. The flow of water in most of 

 our rivers, and in many cases, the flow of water from 

 springs, and the height of the water table in the land, have 

 been most seriously affected by the removal of our forests 

 and should be regarded as the ways by which our water 

 supply is to suffer most severely from deforestation.] 



DISPOSAL OF WATER SUPPLIES. 



"Given a certain amount of precipitation in rain or snow 

 over a certain area, the disposal of the water after it has 

 fallen, and the influence of the forest cover on its disposal, 

 require our attention. For the sake of convenience we 

 can divide the elements which need consideration in this 

 discussion into elements of dissipation, elements of conser- 

 vation, elements of distribution. 



"The difference in effect between the first two classes of 

 elements will give us an idea of the amount of available 

 water supply or run-off resulting from precipitation, while 

 the third class bears upon the methods of distributing the 

 available water supply. 



ELEMENTS OF DISSIPATION. 



"Elements of dissipation are those which diminish the 

 available water supplies ; they are represented in the quan- 

 tity of water which is prevented by interception from 

 reaching the ground, in the quantity dissipated by evapo- 

 ration, in the quantity used by plants in their growth, and 

 in that used by transpiration during the process of growing. 



''Interception. The amount of rainfall and snow which 

 is prevented by a forest from reaching the soil varies con- 

 siderably according to the nature of the precipitation and 



