LUMBERING IN PINE EEGION OF CALIFORNIA. 33 



life under most conditions throughout the rest of the Sierras is one 

 season for the main Hne and two seasons for the back line. Under 

 favorable conditions in the central Sierras, where the soil is loose, 

 the average hfe of the main Une is eight months. On other opera- 

 tions where large machines are used on rough chances the average 

 life is from two-thirds to one season for the main line and two sea- 

 sons for the back hne, with considerable sphcing. Usually it will 

 not be far wrong to estimate an average hfe of one season for main 

 lines and two seasons for back hnes. Main Hnes on Dolbeers last 

 only about two-thirds of a season and the same is true for very 

 large yarders working under severe conditions. 



In addition to cables, supplies and repairs are included in mainte- 

 nance. Supplies consist of oil, grease, tools, blocks, repair parts, etc. 

 The amount required is of course larger for the larger machines. The 

 cost per 1,000 is, however, much the same in different operations 

 under similar logging conditions without much regard to the size of 

 the operation. As a rule, it is from 6 to 9 cents per 1,000. The cost 

 of repairs varies to some extent with the size of the operation. Large 

 operations ordinarily have more efficient shops than smaller ones. 

 The repair crew at the usual donkey camp of from three to five ma- 

 chines is one donkey doctor, one blacksmith, and one blacksmith's 

 helper. At some of the sm aller camps the helper is eliminated. On 

 other operations one donkey doctor may look after the machines in 

 two camps. The board and wages of the repairmen amount to from 

 8 to 10 cents per 1,000, of which it is judged about four-fifths is charge- 

 able to yarding. In addition some of the heavier repair work is done 

 at the mill shop. Also one or two machines are usually overhauled 

 and repaired at the shop each year between logging seasons. Giving 

 consideration to all these factors the information at hand indicates 

 that the cost of maintenance in donkey yardmg is normally from 18 

 to 22 cents per 1,000. 



OVERHEAD YARDING. 



The use of this system has only just begun in the sugar and yellow 

 pine region. Many operators are considering it as a means of ro- 

 ducii)g operating costs, but they do not foci that the machinery now 

 oa the market meets their requirements. A few loggers have been 

 trying out systems of their own devising during the last two seasons, 

 and one or two staiuhird rigs have boon cinployod. 



Two main systems arc in use in the large tim])er of the Pacific 

 Northwest. Both are alike in principle, having a main or standing 

 one Hupportof] at cIUkm* end, upon which a carriage is operated. In 

 one system this main lino is slack(;d off in order to allow the logs to 

 ho attached to llu; carriagf^; then i]\() main lino is tightened, which 

 57172°— Bull. 410—17 3 



