17 



TKEES MAY PKODUOE RAIN. 



It is. usserted by Bome meteorological writers, that trees attract clouds 

 'from a distance, aod cause them to discharge their watery contents in places 

 Over which they would otherwise have been wafted, to dispense their trea- 

 sures upon far distant lands. Though it is not probable that this is so to any 

 considerable extent, it is evident that the coldness of the air in and about 

 forests, causes them to act in the same manner as do mountains in condens- 

 ing the vapors. Whatever tends to ■cool a moist atmosphere saturated with 

 aqueous vapor, causes rain; and it may often happen that the conditions 

 are such, that the slight depression of temperature caused by forests is suf- 

 ficient to produce this efifect. 



On the hot and dry plains of our south-western territories we often, see 

 clouds passing'overhead that reserve tbeiT contents until they have passed 

 from those almost desert regions. Th'ese clouds frequently present all the 

 usual appearance of rain in the higher regions of the atmosphere, and the 

 fertile giving drops are seen to fall far down towards the earth, only to be 

 dissolved and dissipated in the lower strata of air heat«d by the reflection 

 from the parched earth, which these rain drops do not reach. It is quite 

 fiosaible and eVen probable, that a forest, could one be induced to grow there, 

 would so cool the surface as to cause these showers of rain to reach th« 

 ground and thus render such forest permanent. 



HOW TREES AFFECT THE WINDS. 



Besides the very important influence forests exert upon the temperature 

 and humidity of the air, they afford protection from the bad 'effects of high 

 winds; both from the cold northwest winds of winter, and the hot, dry. 

 South-west winds of summer. Any one exposed to the full blasts of either of 

 these winds upon a high pTairie, would very gladly welcome the friendly 

 protection of forest-treeS, among which he could pursue his avocation with 

 comparative ease and comfort, listening to the whistling of the fierce winds 

 above the tree-tops, but free from their evil consequences. To clear away 

 the forests from the state is therefore to expose it and aS Us inhahitants to the 

 Tnimg and blighting effects of these mnds which will mieep over the surface 'with 

 unabated violence. 



If the trees would not stop entirely the strong currents of the wind to 

 "which the state of Wiscolisin is subjected from its vicinity to the great lakes 

 on the one hand, and the greater plains and prairies on the other, being it- 

 self in part a prairie ; and that which was not prairie at the first settlement 

 fast becoming so, they would certainly have great influence in modifying 

 those currents. Whether we adopt the theory that the motion of the 

 wind be that of a soft body rolling over the surface of the earth, or if a 

 "body sweeping along like the current of a river, slightly retarded by contact 

 with the upholding surface., need not be discussed or decided. In either 

 Kep. 2. 



