ARBORICULTURE 



A MONTHLY MAGAZINE. 



Published in the Interest of the 

 International Society of Arboriculture. 



Subscription, $1.00 per annum. 



John P. Brown, Editor, Connersville, Indiana 



Volume II. 



Indianapolis, July, 1903. 



Number 6. 



"j-iRAB 



Phenon^inal Meteorological Conditions — Do Forests 



Control Them? 



The Atlantic States, where evapora- 

 tion is abundant and precipitation is usu 

 ally quite regular, have for the time 

 changed climatic relations with the arid 

 West. While the plains and prairies, 

 which are far removed from seacoast, 

 and the ordinarily cloudless skie^ of Col- 

 orado have been replaced with dense 

 masses of oversaturated air currents, 

 which have poured their contents in dis- 

 astrous floods along the slopes of the 

 Rocky Mountains and the plains and 

 prairies as far as the Mississippi Eiver, 

 meantime a prolonged drought in ISTew 

 York and New England has contributed 

 to siipport the forest fires, the sky being 

 obscured by dense bodies of smoke. 



WHAT HAS CAUSED THESE CHANGED CON- 

 DITIONS. 



The theory accepted by scientific au- 

 thorities in regard to moisture and arid- 

 ity is that water evaporated by heat as- 

 cends into the atmosphere, forms clouds, 

 which wind currents bear inland from 

 the ocean. As temperature is reduced, 

 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 contro" 

 the deposit of moisture of which author- 

 ities are ignorant. 



— Electric 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. 



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 conveyance, yet 

 with violence wlieu a single tree becomes 

 the object which receives and communi- 

 cates the bolt. 



Through the influence of a great for- 

 est, clouds are attracted and caused to 

 precipitate part of their moisture. 



High mountains perform the same 

 service, as they become the means o 

 communicating electric currents. A 

 plain from which fires have removed all 

 trees and prevented others from growing 

 has not the power of influencing air cur- 

 rents, and, as a rule, clouds pass over 

 them. At long intervals extraordinary 

 electrical disturbances occur and moist- 

 ure is precipitated in unusual quantities 

 during a brief period, causing freshets in 

 valleys which were dry beds a day before. 

 Such storms have been given the term, 

 cloudbursts. Upon Pike's Peak, along 

 the chain of lakes which supply Colorado 

 Springs with water, are telephone lines, 

 as well as telegraph stations. Upon the 

 supporting poles, above the wires, is a 

 common barb fence wire, maintained a; 

 a lightning arrestor. Here on the moun- 

 tain electrical disturbances are of com- 

 mon occurrence, and it is necessary to 

 ])rovide safety conductors, rain and snow- 

 storms being frequent. 



