18 TREE CULTUKE IN SOUTH AUSTKAIIA. 



when the rain falls upon it a considerable proportion of this ascends again 

 in the form of a hot steam, and is of course lost ; and, secondly, by hot 

 and dry winds blowing over the surface of the sheet of water in the 

 reservoir a very considerable proportion of water is evaporated. Here, 

 again, the effect of covering the ground with trees would be of great 

 advantage. Speaking of tanks in India of a similar character to oiir 

 reservoirs. Dr. Brandis (the Inspector-General of Forests for the Govern- 

 ment of India) says : — " Now, the effect of clothing the catchment area 

 of these tanks with trees, grass, and brushwood, will certainly be to 

 diminish evaporation, and thus to increase the amount available for the 

 tanks. "We may conclude from Mr. Culcheth's experiments that the 

 quantity now lost by evaporation amounts to five-sixths, on an average, 

 of the rain-water that falls upon the catchment area ; but with 

 diminished evaporation the flow into the tanks from a wooded area will 

 be much greater than from a bare surface." 



Another advantage which would accrue to the reservoirs" of this 

 country by the planting of their catchment areas with trees, would be that 

 in summer time many clouds charged with vapour woxdd be attracted by 

 the coolness hovering above the trees, and the result would most probably 

 be a deposit of rain, which would otherwise have passed on had the 

 surface been bare and dry. 



I have therefore to recommend that, as a means towards the saving of 

 water, the catchment areas of our reserv'^oirs should be planted with 

 suitable kinds of trees. Even the small spaces of ground devoted to 

 dams by the farmers in the Northern Areas could very judiciously be sur- 

 rounded and protected by trees, and thus be made serviceable for timber 

 as well as water. 



