60 BULLETIN 711, U. S. DEPAETMENT OF AGRICULTURE. 



scriptive terms; or the second unci third hauls may be denominated 

 " swinging." The terms are loosely used by the industry, however, so 

 that for clear and accurate discussion, definition of terms is neces- 

 sary, which in the very nature of the case must be more or less ar- 

 bitrary. 



The term " yarding " in this bulletin is confined to the first haul, 

 which takes the log at the stump. Swinging is considered as trans- 

 portation that delivers the log from the yarding engine to a pole 

 road, chute, railroad, or drivable stream. One or more engines, of 

 either ground or overhead type, may do the work, but always in con- 

 nection with very temporary improvements. Roading is considered 

 as the transportation of logs bj^ a logging engine or engines in con- 

 nection with improvements that are to some extent permanent in 

 character, such improvements consisting of pole roads, chutes, over- 

 head cables, etc. 



YARDING. 



METHODS. 



Power yarding is done in three ways : First, with the log dragging 

 on the ground and the haul-in or main j^arding line leading along 

 the surface of the ground from the yarding engine to the log; sec- 

 ond, with the log dragging on the ground and the main yarding line 

 leading from the yarding engine to a large lead block suspended 

 near the top of a spar tree standing close by and thence out to the 

 log; third, with the log riding suspended, or partly suspended, from 

 an overhead cable. The first system is known as ground yarding ; the 

 second, as high-lead yarding; and the third, as overhead yarding. 

 In addition to these three yarding sj'stems, there are a great num- 

 ber of methods and a great variety of labor, equipment, and supplies 

 used in yarding ; more than in any other step in the logging opera- 

 tion. 



FACTORS INFLTJENCING THE OUTPUT. 



Yarding output, the chief element determining cost, is of utmost 

 concern to both the operator and the timber appraiser. Influenced 

 as it is by a great variety of factors, it is hard to estimate. Com- 

 panies that use a bonus system have proved that abundantly, and 

 they possess ever}' advantage in the shape of records and time, aside 

 from the inducement to make an intensive examination of the terri- 

 tory. The appraiser, who must estimate yarding output at whole- 

 sale and after a far less thorough examination, is at a great disad- 

 vantage. Following are the factors to be considered. No attempt is 

 made to present them in the order of their importance. They are 

 treated in more detail under the specific methods. 



