24 BULLETIN 440, U. S. DEPARTMENT OF AGRICULTURE. 



bumper logs on one or both sides of the track. The cost differs with 

 the amount of clearing and grading necessary. The average is from 

 one-haK to one day's work for a yarding crew, or from $20 to $40 

 each, or say, 2 cents per 1,000. In the open stands of yeUow pine a 

 combined bucking chute and landing is used. The landing consists 

 of three logs and a bumper log, and the chute is about 250 feet in 

 length. The average cost is $100, or about 7 cents per 1,000. The 

 most expensive type of landing is that used in a long logging opera- 

 tion on very steep ground. A large excavation must be made in the 

 upper bank of a railroad cut, and bucking chutes 250 feet long are 

 built out in two directions. The average cost is about $300 each, or 

 approximately 8 cents per 1,000. 



Equipment. — Donkeys are ordinarily classified by the size of the 

 cyhnders, the diameter being given first. The original yarding 

 donkey was the Dolbeer or spool type, which is now used mainly for 

 chute and trestle construction. The standard size Dolbeer has a sin- 

 gle 6 by 12 inch cyhnder and weighs about 8,000 pounds. The boiler 

 is 36 by 6 inches and carries 160 pounds of steam. It is manufactured 

 in San Francisco and the cost f. o. b. factory is about $1,000. This 

 type has a spool for the yarding Hne and may have a single drum for 

 the back Hne. The usual maximum yarding distance is 800 or 1,000 

 feet. 



Practically aU the other machines used are return line. All of the 

 engines have two cylinders and are connected by gears to the shafts 

 of two drums, one for the yarding line and one for the back line. 

 These gears may be either direct or compound. Compound gears give 

 greater speed. The drimis, placed either tandem or opposite, rotate 

 upon their shafts and are held fast when puUing by means of frictions, 

 which are apphed by hand levers. The newer and larger yarding 

 engines have steam frictions on the maia drum. A spool or small 

 friction drum may be attached to the shaft of the main drum for 

 loading purposes. 



The boilers are upright, ranging in size from 48 inches in diameter 

 and 118 inches in height to 72 inches in diameter and 144 inches in 

 height. Some of the newer types have so-called extension fire boxes 

 which give larger firing space. The boilers of the older types of 

 engines carry about 160 or 165 pounds of steam. The newer types 

 carry from 175 to 200 pounds. It is important in any yarder to have 

 sufficient boiler space to keep up steam pressure, especially in the 

 mornings or after showers, when the fuel is wet. 



SmaU. machines, such as 10 by 11 inch tandem drum yarders, and 

 9i by 10 inch and 9 by 10^ inch compound yarders, are used in the 

 yeUow pine stands on the east side of the Sierras. Light, rapid ma- 

 chines which can be readily moved are required because the timber 

 is small and the stand open. Machines of these sizes are usually sup- 



