692 



Yearbook^ of Agriculture 1949 



in the horizontal position for felling 

 or in the vertical position for bucking. 

 Either type of power saw, properly 

 handled by a well-trained crew, enables 

 the crew to cut twice as much wood 

 per man-day as would be possible with 

 hand tools. Portable circular slasher 

 saws are now commonly used to cut 

 short pulpwood and millwood bolts 

 from tree-length second-growth poles 

 skidded into the landing. Powered 

 chain conveyors are in use to carry the 

 bolts from the saw to the hauling ve- 

 hicle or to a pile. Such equipment can 

 buck up to 80 cords of 4-foot wood a 

 day. 



SEVERAL OF THE WAR-BORN devices, 

 developed for other uses, are being 

 adapted for use in the woods. Electric 

 generators that produce alternating 

 current of 180 to 360 cycles (the stand- 

 ard frequency is 60 cycles) make pos- 

 sible electric motors of smaller size 

 and lighter weight for use as chain-saw 

 power units. High-pressure hydraulic 

 systems utilizing synthetic rubber tub- 

 ing are being employed in light and 

 extremely flexible loaders. One of 

 these, mounted on a crawler tractor, 

 has hydraulically operated arms that 

 can be used to gather up a cord of 

 wood just as a boy picks up an armful 

 of stove wood. The hydraulic arms can 

 push the load along on the ground, 

 lift it into the air to a height of 12 

 or 15 feet, swing it around to any 

 desired position, and drop it into a 

 truck or railroad car. Another type of 

 hydraulic crane, mounted on a truck, 

 can revolve a full circle. Hydraulic out- 

 riggers push out from the base of the 

 machine to the ground and thereby 

 stabilize it while it is in use. The boom 

 is extensible and the cable is pulled 

 in by hydraulic power. It has an 

 hydraulically operated grapple for use 

 in picking up short wood. 



The principles of package handling 

 are also being adapted to logging. Steel 

 straps and cables are used to bundle a 

 cord or more of short bolts or long 

 logs for more convenient handling dur- 

 ing transshipments. Pallets of wood and 



tubular steel devices are used as pack- 

 aging for short bolts. Some of them can 

 be loaded, skidded through the woods, 

 and pulled up a ramp onto a truck 

 and off again at the mill. 



There are also some developments in 

 cable skidding particularly in light, 

 fast equipment that reduces the dam- 

 age to the remaining trees. One west 

 coast inventor has put his motive power 

 and the operator into a carriage that 

 rides on a skyline. A winch in the car- 

 riage hoists the bundles of logs up 

 under the carriage; then the carriage 

 pulls itself along the skyline to the 

 landing. The new equipment can carry 

 tractors and the other heavy equipment 

 into otherwise inaccessible places. 



Swiss engineers have developed sev- 

 eral extremely light cable-logging sys- 

 tems to bring small logs or bundles 

 of wood off steep slopes. One consists 

 of an endless cable (suspended from 

 trees) , which makes a circuit from the 

 cutting area to the landing. The cable 

 runs through star-shaped wheels. In- 

 dividual bolts of wood are hung on 

 the line by one crew at the cutting area 

 and taken off by another at the landing. 



Rubber treads are being tried now on 

 crawler tractors to make them more 

 adaptable to the rocky terrain. A hy- 

 draulic braking device, developed to 

 arrest heavy planes landing on the 

 decks of carriers, has been used to hold 

 trucks to a predetermined speed as 

 they come down steep slopes. Fluid 

 drives are being used in cable skidders, 

 tractors, motortrucks, and sawmills. 

 That type of transmission gives greater 

 capacity to absorb shocks and to take 

 overloads. 



New steel alloys are utilized to im- 

 prove cutting tools of all sorts axes, 

 circular-saw teeth, and chain-saw 

 teeth. New explosives and earth-mov- 

 ing machinery are also finding their 

 place in logging-road construction. 

 Prefabricated bridge units are also be- 

 ginning to find use on these roads. 



Some of these developments have 

 been set-backs to the development of 

 forest-management practices. Early 

 logging methods were not particularly 



