Table 4.— Machine utilization^ rates for the tree processor and 

 chipper 



Harvest block 



Processor 



Chipper 





Percent 



Percent 



Arl<ansas Creek 



65 



63 





70 



79 



Sunflower Road 



36 



71 



Sheep Flats 



72 



70 



^Computed from study data: 







Net time 



Gross time - Downtime 





Gross time 



Gross time 





Gross time = 



Time under observation. 





While a portion of this low rate was due to lack of sawable 

 material, a sizeable portion was due to an overabundance of 

 chippable material. That is, the chipper could not chip the 

 small stems fast enough to keep the landing from becoming 

 clogged with this material. The tree processor, as a result, was 

 forced to help feed the chipper and to spend an excessive 

 amount of time sorting sawable and chippable material. Thus, 

 the mix of size classes affects how efficiently the system 

 operates and therefore affects overall productivity. 



Component Productivity 



Felling, bunching and skidding. — Skidding production data 

 are shown in table 5. The lowest total daily net production was 

 in the Arkansas Creek block, which may have been due to in- 

 experience with the harvest system. Bunches of trees were not 

 properly oriented with respect to the landing in this block. 

 Total daily net production at the Sunflower block was next 

 lowest. This may have been due to the steeper slopes (25 per- 

 cent) and a relatively large percentage of small trees chipped for 

 hog fuel. 



Table 5.— Felling and skidding production 



Tons/day '-block average 



Area 



Item 



Hog fuel 



Logs 



Total 



Arkansas Creek 



Shears 



527 



50.1 



102.8 





Skidders 



120.8 



114.7 



235.5 



Gold Creek 



Shears 



67.2 



72.5 



139.7 





Skidders 



148.5 



160.2 



308.7 



Sunflower Road 



Shears 



49.6 



24.9 



74.5 





Skidders 



177.8 



89.3 



267.1 



Sheep Flats 



Shears 



83.1 



134.2 



217.3 





Skidders 



119.4 



192.8 



312.2 



Operational days = (total hours-unnecessary downtlme)/8 hours. 



Two different kinds of feller-bunchers were employed. An 

 International tracked (Model No. 3966-B) feller-buncher ac- 

 counted for most of the volume logged in the study. The re- 

 mainder of the felling was accomplished with a Melroe Bobcat 

 (Model No. 1079) feller-buncher. Average production rates for 

 each machine are presented in table 6. They ranged from 343 

 to 511 trees per day for the International and from 51 1 to 562 

 trees per day for the Bobcat. 



Table 6.— Production rates for feller-bunchers (block average) 



Area Machine Trees/day' Utilization 









Percent 



Arkansas Creek 



International 



343 



85 



Gold Creek^ 



International 



511 



88 





Bobcat 



612 



85 



Sunflower Road 



International 



470 



86 



Sheep Flats" 



International 



386 



85 





Bobcat 



562 



81 



Based on the time study samples expanded to an 8-tiour shift, downtime 

 induded. 



^Utilization = (total time-downtime)/total time. 



^The Bobcat worked on slopes less than 10 percent; the International, 

 slopes up to 30 percent. 



The Bobcat was used mainly in thicker, smaller diameter portions of the 

 stand. 



Several factors affected the International tree shear produc- 

 tion. The operator was new to this kind of work and gained ex- 

 perience on the Arkansas Creek block. There was a decided im- 

 provement in the orderliness and efficiency of his work in the 

 remaining three blocks. The spacing of leave trees also was a 

 factor, with the operator having greatest freedom in the clear- 

 cut situation. Heavy branches, which lodged in adjacent tree 

 crowns, affected handling of the sheared trees. The size of the 

 trees cut had little effect on the shearing and bunching time, 

 unless the stand was so thick that several small stems could be 

 sheared at once. Also, the International feller-buncher did not 

 have an accumulator, so it had to lay down each tree as it was 

 sheared. 



The International shear easily felled and bunched trees up to 

 the capacity of the shear opening; i.e., 18 inches (45.7 cm) at 

 the ground level. The Bobcat shear had trouble with the taller 

 trees over 14 inches (35.6 cm) d.b.h. The International shear 

 seemed quite adequate for trees up to 18 inches (45.7 cm) at 

 ground level, on slopes up to 30 percent. Because of its small 

 size, the Bobcat had trouble with large trees on slopes over 

 10 percent. Under favorable conditions (flat ground, small 

 stems, etc.), the Bobcat was slightly more productive than the 

 International machine. Because the Bobcat could travel fast 

 with a sheared stem, the operator made larger bunches, which 

 raised skidding production. 



Skidding was done by two John Deere Model 640 rubber- 

 tired skidders. One machine was equipped with a grapple, the 

 other with standard chokers and winch. The machines generally 

 performed different functions, so direct comparisons of pro- 

 duction were not possible. Time study data, however, did con- 

 tain information on hook/unhook time, which provided a basis 

 for comparison with respect to one of the factors that in- 

 fluences production. Table 7 gives hook/unhook times for the 

 two skidders. 



The table shows that hook time for the grapple machine was 

 considerably less than that for the choker machine. Unhook 

 time was more similar, though the grapple machine still re- 

 quired less time. 



7 



