PEESIDENT S ANNUAL ADDRESS. 2$ 



have been materially injured by denudation; and on the other 

 hand, rain has become more frequent in Egypt since the more 

 vigorous cultivation of the palm trees.' " 



Barth says on the same subject: "The ground in the forest, 

 as well as the atmospheric stratum over it, continues humid after 

 the woodless districts have lost their moisture; and the air charged 

 with the humidity drawn from them is usually carried away by 

 the winds before it has deposited itself in a condensed form on 

 the earth. Trees constantly transpire through their leaves a great 

 quantity of moisture, which is partly absorbed again by the same 

 organs, while the greater part of their supply is pumped up through 

 their widely ramifying roots from considerable depths in the 

 ground. Thus a constant evaporation is produced which keeps 

 the forest atmosphere moist even in long drouths, when all other 

 sources of humidity in the forest itself are dried up." 



Another author says: "The rainless territories in Peru and 

 North Africa establish this conclusion, and numerous other ex- 

 amples show that woods exert an influence in producing rain, and 

 that rain fails where they are wanting — for many countries have 

 by the destruction of the forests been deprived of rain, moist- 

 ure, springs and watercourses, which are necessary for vegetable 

 growth. In Palestine and many other parts of Asia and North- 

 ern Africa, which in ancient times were the granaries of Europe, 

 fertile and populous, similar consequences have been experienced." 



Savignat arrives at this conclusion: "Forests on the one hand 

 diminish evaporation; on the other they act on the refrigerating 

 causes. The second scale of the balance predominates over the 

 other, for it is established that in wooded countries it rains oftener. 

 and that, the quantity of rain being equal, they are more humid." 



Boussingault, after examining this question with much care, 

 remarks : "In my judgment it is settled that very large clearings 

 must diminish the annual fall of rain in a country." 



Some writers dispute the assertion that the total annual quantity 

 of rain is increased or diminished by the destruction of the woods, 

 but a very large majority strongly affirm that the rainfall is greater 

 in wooded than in open countries. None dispute the fact that 

 forests act as a reservoir and cause an even distribution of the 

 water, thereby preventing floods and droughts. 



The following passage occurs in a report to the legislature of 

 Massachusetts in 1846: 



"The importance of forests as furnishing material for shipbuild- 

 ing and numerous other arts is so obvious that it must occur to 



