22 I'RACTICAL ARBORICULTURE 



PHENOMENAL METEOROLOGICAL CONDITIONS DO FORESTS 



CONTROL THEM? 



In 1903 the Atlantic States, where evaporation is abundant and precipi- 

 tation is usually quite regular, for the time changed climatic relations with the 

 arid West. While the plains and prairies, which are far removed from sea- 

 coast, and the ordinarily cloudless skies of Colorado were replaced with dense 

 masses of oversaturated air currents, which poured their contents in disastrous 

 floods along the slopes of the Rocky Mountains and the plains and prairies as 

 far as the Mississippi River, meantime a prolonged drought in New York and 

 New England contributed to support the forest fires, the sky beino- obscured by 

 dense bodies of smoke. 



WHAT CAUSED THESE CHANGED CONDITIONS? 



The theory accepted by scientific authorities in regard to moisture and 

 aridity is that water evaporated by heat ascends into the atmosphere, forms 

 clouds, which wind currents bear inland from the ocean. As temperature is re- 

 duced, precipitation occurs. Having parted with all surplus moisture during 

 the early part of their journey, there is none left with which to moisten the 

 earth throughout the central portion of the continent, and thus it is arid. 



But there are influences which control the deposit of moisture of which 

 authorities are ignorant. 



ELECTRfc INFLUENCE. 



Cloud movements, ability to retain moisture and precipitation are largely 

 caused by electrical energy, and this is controlled by obstacles in the pathway 

 of air currents, such as mountains and forests. 



LIGHTNING. 



Electricity passes between cloud and earth to maintain an equilibrium. 

 gently at times, as every twig in a forest bears its part in aiding this convey- 

 ance, yet with violence when a single tree becomes the object which receives 

 and communicates the bolt. 



Through the influence of a great forest, clouds are attracted and caused to 

 precipitate part of their moisture. 



