30 BULLETIN 440, U. S. DEPAETMENT OF AGEICULTUEE. 



Water is supplied both by pumping and by gravity. A horse is 

 required at each machine for shifting cable when changing runs. 



One company in the southern Sierras uses 12 by 14 inch yarders 

 with IJ-inch cable for yarding distances up to 2,000 feet. The 

 country is one of steep slopes on both sides of numerous streams in a 

 common watershed. The logging railroad follows contourwise along 

 these slopes. The machines are set along the railroad, and the 

 logs are yarded to the track, both up and down hill. The slopes 

 above the track range from 25 to 40 per cent, and those below the 

 track from 40 to 70 per cent. The surface is smooth and there is 

 little underbrush. The virgin stand is about 40,000 feet per acre. 

 The logs are yarded in long lengths and bucked at each yarder with 

 a steam saw. The daily output is about 38,000 or 40,000 feet, with 

 the followmg crew: One hooktender, 1 frogger, 3 riggers, 1 choker- 

 hole digger, 2 frog shovelers, 1 whistlepunk, 1 engineer, 1 fireman, 1 

 woodcutter, and 1 wood teamster. 



The average outputs given in the above examples include a time 

 allowance for movuig donkeys, but not the building of frogs or land- 

 mgs. It is usually more economical to have landings built by separate 

 crews than by the yarding crew. In easy country a donkey will make 

 the usual one-fourth or one-third mile move under its own power m 

 one-half day. In rough country double that time is required. The 

 donkeys are frequently moved on flat cars on the logging railroads. 

 From three-fourths to one day is required for such a move, regardless 

 of distance. Moving time is measured from the bringmg in of the 

 last log on one setting until the line is out ready for logging on the 

 next. Light donkeys are moved more quickly than heavy ones. 

 The period between moves depends upon the output of the donkey, 

 the stand per acre, and the area of the setting. It usually ranges 

 from three weeks to two months. 



The usual time of changing a tailblock from one run to another is 

 from 20 to 30 minutes, depending upon the character of the country. 

 More difficult changes, or changes around several runs, require from 

 30 to 50 minutes. EHminating very unfavorable settings, the aver- 

 age time required for a turn is about 15 minutes. On short hauls, it 

 may be as low as six or seven minutes, and on long diflacult hauls, as 

 high as 25 minutes. The size and speed of the machine and the 

 character of the timber and topography aU affect the time of a turn, 

 but when delays due to loading, bucking, or frogging are considered, 

 the average for most operations is about four turns per hour. The 

 following information regarding the time of logging turns is intended 

 only to give the approximate relation of the various parts of each 

 turn. In a yellow-pine stand under very good conditions a 10 by 

 11 inch tandem drum yarder hauling 1,200 feet averaged a turn in 13 



