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AERIAL LOGGING 



Aerial logging, with main spar at loading engine. Lidgerwood iMfg. Co., Liberty St., New York. 



By the railroad track, a Lidgerwood engine is placed close to a "main spar tree," which must 

 have a diameter of 24 inches at a height of 60 feet above ground. At a distance of 900 feet from the 

 spar tree, at the circumference of the circular district to be logged at one "setting," there is selected a 

 "tail tree." 



The main standing cable, 1' , inches in diameter, extends over the main spar tree to the tail tree. 

 The ends of this cable are fastened tightly to stumps. The slack is taken out by a cable run over one 

 of the spindles of the buUdonkey. The top of both the spar tree and the tail tree are secured by guys to 

 stumps nearby. 



On the main cable runs a carriage consisting of a double travelling block and supplied with loading 

 lines, tongues or chokers. 



The carriage is played rapidly to and fro, between tail tree and spar tree, by the "skidding rope," 

 and the "outhaul rope." The "slack pulling rope" feeds the skidding rope out to the tong-hookers. 

 The skidding rope is a ^j-inch cable, and the slack pulling rope is a ^,-inch cable. 



The skidding line is said to last about a year, and the standing line may last as long as 18 months. 

 The capacity of a rig averages 40,000 feet per day. 



Two main standing cables are used ; one is put up while the other is being used, so as to prevent 

 delays. The tail trees are selected at distances of 150 feet one from the other. 



A full crew for the rig consists of 15 men (skidder, loading leverman, fireman, woodcutter, 3 loaders, 

 2 tong hookers, 1 signal man, 1 tong shaker, 4 riggers). 



The catalog of the Lidgerwood Manufacturing Co., 96, Liberty Street, New York, contains interesting 

 information pertaining to aerial log transportation. 



For logging uphill out of deep canyons, aerial transportation is the only system feasible. The system 

 can be used with a portable steel main spar base, where there are no main spar trees conveniently located 

 along the line of the railroad. 



The cars are loaded with a swinging loading boom or with a guy loading arrangement, by one and 

 the same engine. 



