Table 1 . --Power requirements for producing fingerling chips with the Forest Service 



spiral head chipper 



: No. : : 



Species : sample : Specific gravity : Specific power 



Hp/min 



Lodgepole pine 12 0.413 - 0.466 8.7 



Douglas-fir 1 - 8.1 



Larch 8 .492 - .515 9.2 



Aspen 8 .343 - .377 5.2 



Basswood 7 .278 - .318 5.2 



Red oak 6 .510 - .549 9.3 



Sugar maple 3 .618 - .658 15.1 



could be met by portable units. Envisioned are field operations similar to whole-tree 

 chipping operations now commonly producing pulpwood chips. 



A conceptual field unit is shown in figure 4. A portable unit can be constructed 

 for an estimated $35,000. Using a 6-year life, straight-line depreciation, and 15 

 percent interest and contingency rates, the hourly operating cost is estimated at 

 $12.48. Based on an average 6-inch-diameter log and 60 percent feed rate, production 

 is estimated to be 15 tons per hour (table 2) . 



Figure 4. — Concept of mobile unit for producing fingerlings. 



4 



