CHAPTER XIII 

 POLES AND PILING 



GENERAL 



WITH the advent of the telegraph and later the telephone as means of 

 communication there was created a great demand for poles on which the 

 wires are supported. Still later the street railway and interurban 

 trolley systems and the electric light and power transmission lines added 

 very materially to this demand until, at the present time, between 

 4,000,000 and 5,500,000 poles valued at from $8,000,000 to $10,000,000 

 are now annually needed for new construction and renewals due to failure 

 from breakage or decay. 



No government statistics have been published to show the amount of 

 piling annually used in this country, but it is estimated that nearly as 

 much timber is utilized for piling as for poles. When one takes into 

 consideration the great quantities of piles used for bridge construction, 

 trestle, wharf and harbor work along rivers, lakes and seaports, it is evi- 

 dent that the annual consumption of this form of material must be very 

 large. 



At first, practically all species were used for poles and piles. Acces- 

 sibility and initial cost determined very largely the timbers used for our 

 first telegraph and telephone lines, but it was soon discovered that most 

 poles decay at the ground line in from two to five years. 



At the present time even our most durable species are being treated 

 with some wood preservative to prolong their service in the pole lines. 



QUALIFICATIONS DESIRED IN POLE AND PILE TIMBERS 



In making a selection of the various woods available for poles, the 

 following properties are the determining factors: 



i. The wood must be durable in contact with the soil. Poles decay 

 most rapidly at the ground line because of the alternate dry and moist 

 conditions at that point. Since poles are used in the round almost 

 exclusively, it is important that the sapwood be durable. 



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