Figure 7. — Sheared logs decked for loading. 



Figure 8. — An accumulation of tops and limbs 

 from the tree processor. 



Whole-tree chipping. — The average production rates in tons 

 per day are given in table 8. A high of nearly 180 tons (164 

 tonnes)/day was achieved in the Sunflower block and a low of 

 about 120 tons (109 tonnes)/day at the Sheep Flats block. 

 Although the average utilization rates of the chipper are similar 

 in all blocks (table 4), production rates varied considerably. 

 (See also appendbc C for daily productivity utilization.) Much 

 of the variation was due to the kind of material chipped. In the 

 Sunflower block and the Gold Creek block, many of the stems 

 skidded to the landing were just under saw log size, were quite 

 tall, and had few limbs (larch and lodgepole pine). This 

 material produced more chips at a faster rate than the limbs 



and tops, which provided a greater proportion of the input of 

 the Arkansas and Sheep Flats block. 



Saw log recovery (M bd. ft. /acre) was less than the preharvest 

 cruise indicated. We attribute this to the difficulty of judging 

 whether a small (marginal) tree will produce the minimum-sized 

 log, especially from the cabs of the tree processor or whole-tree 

 chipper. Apparently, the marginal trees looked smaller than 

 they really were. For example, the Gold Creek block contained 

 many marginal saw log stems. The cruise estimated a recovery 

 of 1 1 .5 M bd. ft. /acre. The actual recovery was 7.5 M bd.ft./ 

 acre. Identification of marginal saw log trees may or may not 

 be a problem, depending on the relative values of marginal logs 

 and whole-tree chips. 



The chipper used in this study was set up to produce 3/4- to 

 1-inch chips. Hog fuel specifications, however, allow chip 

 thicknesses up to 2 inches (5.1 cm). The chipper operator sug- 

 gested that if his machine were modified (a standard factory 

 procedure) to produce 2-inch (5. 1-cm) chips, chipping rate" 

 would be increased by 25 percent. Such an increase in chipping 

 rate would be highly desirable in areas like the Sunflower 

 block, where chipper capacity limited log production by the 

 tree processor. Production of large chips could cause increased 

 wear on the chip vans, especially on tarps or other areas that 

 receive the full impact of blown chips. 



Chip vans. — The chip vans used in this study were designed 

 for highway use. The investigators had thought that off- 

 highway use would require van reinforcement and that the trac- 

 tors should be geared the same as log trucks. An inquiry was 

 made as to the types of chip vans and tractors used in the Up- 

 per Peninsula of Michigan.^ In that region, special tractor gear- 

 ing or chip van reinforcement is not considered necessary. Ap- 

 parently, there is also little significant difference in gearing 

 systems between highway and log trucks. Log trucks utilize a 

 slightly lower gear ratio to help them start loads moving on 

 steep grades or soft ground. Even in the Rocky Mountains, 

 whole-tree chipping operations would probably be conducted 

 on reasonably gentle terrain. Also with a whole-tree logging 

 system, skidders would be available to assist trucks. Normally, 

 log loading occurs after skidders have stopped working in an 

 area. 



During the study, chip vans were loaded by blowing chips 

 through the rear door. This often resulted in illegal loads due 

 to poor weight distribution. A possible solution would be to 

 load over the top of the van, using a U-shaped spout that 

 would distribute the chips more evenly. Top filling would also 

 eliminate the unfavorable orientation of the chip vans on the 

 landing (see fig. 2). For landings of limited size without ade- 

 quate turnaround space, this modification would be essential. 

 Figure 9 shows a landing that required much less area than the 

 landings shown in figure 4. Steep terrain limited the landing 

 size. 



^Personal communication with Mike Coffman, silvicultuiist with Champion 

 Timberlands, Lake States Operation, Norway, Mich. 



9 



