Table 7.— Hook/unhook times for John Deere skidders 



Average Average 

 hook time/turn unhook time/turn 



Date Location Grapple Choker Grapple Choker 



Minutes 



8/06 



Arkansas Creek 



0.8 



3.9 



0.63 



0.67 



8/08 



Arkansas Creek 



.4 





.44 





8/11 



Gold Creek 







.40 





8/12 



Gold Creek 



.99 





.37 





8/15 



Sunflower Road 











8/22 



Sheep Flats 



.24 



4.72 



.46 



.78 



8/27 



Sheep Flats 



.59 





.33 





Tree processing. — Average production rates for the tree proc- 

 essor are given in table 8. Daily production rates are given in 

 appendix B. In terms of tons of logs produced per day, the 

 greatest average rate was attained at the Sheep Flats block, 

 nearly 200 tons (182 tonnes)/day, and the least at the Sun- 

 flower block, less than 90 tons (82 tonnes)/day. The difference 

 was probably due to the supply and size of saw log and chip- 

 pable stems and their effect on the system balance. Based on 

 total observed time of the tree processor, production in 

 logs/minute ranged from 0.7 to 1.0, a difference of 144 logs in 

 an 8-hour shift. Because of the extent and type of downtime in- 

 cluded in the total time, these figures are difficult to compare. 

 When all downtime is removed, however, only processing times 

 remain and comparisons become more meaningful. Table 8 in- 

 dicates that logs were processed considerably faster in the Sun- 

 flower and Gold Creek blocks than in the Arkansas Sheep Flats 

 blocks. These differences are largely because larch and lodge- 

 pole pine can be processed faster than limby "bull pine" 

 (ponderosa). 



Tables.— Tree processor production rates 



Whole-tree 

 Tree processor chipped 



Logs/min^ 



Area Tons/day' Total time Net time Tons/acre 



Arkansas Creek 



114.7 



0.7 



1.0 



120.8 



Gold Creek 



160.2 



1.0 



1.4 



148.5 



Sunflower Road 



89.3 



.7 



2.1 



177.8 



Sheep Flats 



192.9 



.8 



1.1 



119.4 



The operational hours (total time - unnecessary downtime) were divided 

 into total tons of logs produced (scale tickets). 



Based on time study data. Total time is full observation period; net time 

 is total time minus all downtime. Appendix A details the tree processor 

 productivity. 



The Hahn Harvester representative said our production was 

 low. He considered one load of logs per hour a reasonable 

 goal. At an average of 90 logs per load, this translates to 1 .5 

 logs per minute. While the net processing rate exceeded this 

 figure in two blocks, the gross rate was only about half that 

 value for the rest of the blocks. The chipping operation may 

 have slowed down the log processor. This happened in the Sun- 

 flower block, where the tree processor had to be shut down on 



several occasions to allow the chipper to catch up. It also hap- 

 pened on the other blocks when the tree processor grapple was 

 used to segregate saw log and chippable material in the turns 

 rather than maintaining a steady supply of tree lengths to the 

 processor. These events were not recorded; however, a low pro- 

 duction rate may be expected when the machine is part of a 

 system that produces both logs and hog fuel. Appendix B pre- 

 sents daily tree processor productivity on both gross and net 

 time basis. Utilization percentage is also shown. These daily fig- 

 ures reflect block differences, daily production problems, and 

 the learning process during the study. 



Of 99 loads of logs produced in the study, about 56 were 

 scaled and inspected under the Champion Timberlands log 

 quality program. Two loads produced in the first harvest block 

 showed total log defects of 36 and 23 percent, respectively. 

 After these two adverse reports were received, a concentrated 

 effort was made to improve log quality by instructing the proc- 

 essor crew in species bucking specifications. The remaining log 

 quality reports averaged 9.3 percent total defect. During the 

 month of the study, log quality reports from the Champion 

 Timberlands operations averaged 12 percent defect. Figure 6 

 shows the quality of delimbed logs. 



Figure 6. — Deck of delimbed study logs. 



Initially, some loggers said that shearing would cause massive 

 defects through "butt shatter" or stem crushing. Such damage 

 was less than one-half inch on most logs. Figure 7 shows butt 

 ends of some sheared trees. The tree butts that were substand- 

 ard were trimmed by the tree processor's hydraulic chainsaw. 

 Stem crushing might have been more severe if frozen trees were 

 being harvested. 



Some machine damage to logs can result if too much 

 pressure is placed on the delimber knives of the tree processor. 

 This pressure is controllable by the machine operator and 

 should not be a problem with an experienced crew. Some 

 "limb pull" defect was noted during the first part of the study. 

 This defect was caused by a slow delimber knife speed that 

 produced more of a pulling than a shearing action. A change 

 to a high-speed sprocket drive on the delimber unit reduced the 

 problem. 



Figure 8 shows accumulated tops and limbs from the tree 

 processor. An overaccumulation of this material plugs up the 

 landing and requires the tree processor grapple to be used to 

 feed the chipper. 



8 



