FORESTS IN TBEIR RELATION TO RAINFALL. 211 



FORESTS CONSIDERED IN THEIR RELATION TO 



RAINFALL AND THE CONSERVATION OF 



MOISTURE. 



By J. H. Maiden. 



[Read before the Royal Society of N. 8. Wales, November 5, 1902. ~] 



SYNOPSIS. 



Page. 



I. Introductory ... 211 



II. The Historical Method 213 



a. General observations ... ... 213 



b. The case " Forest destruction does diminish the rainfall." ... 214 



c. The case " Forest destruction does not diminish the rainfall 217 



III. The vastness of rainfall conditions 



IV. Clouds may strike against trees and deposit moisture 



V. Not merely a question of large trees 



VI. Eainfall Measurements in forests and open country 



VII. Physiological action of trees — transpiration 



VIII. Some uses of forests : ... ... 



a. To temper floods ... ... 



b. To conserve springs and to aid in the more even 



tion of terrestrial waters 



c. To prevent evaporation of water... 



d. To give shelter to stock, crops, etc 



... 221 



... 223 



... 226 



... 227 



... 228 



... 231 



... 231 

 distribu- 



... 233 



... 237 



... 238 



e. The leaves of forest trees etc., afford manure and mulch ... 239 



I. Introductory. 

 I bring before you the subject which is often conven- 

 tionally known under the title of "Forests and Rainfall," 

 and in regard to which it may be fairly said that there still 

 exists, in New South Wales at least, a considerable amount 

 of misapprehension. Even the clear cut statements of Mr. 

 Russell, our Government Astronomer, that forests do not 

 increase rainfall, have failed to carry conviction to some 

 people, for the reason, I take it, that the broader subject of 

 the effect of vegetation on the conservation of moisture has 



