HARVESTING SYSTEMS FOR RESIDUE 



Research suggests that the most efficient time to harvest logging residue is in 



conjunction with the commercial harvesting, especially when clearcutting, because the 



entire tree can usually be removed in one operation. An alternative method is to re- 

 move part or all of the residue after commercial harvesting. 



Previous studies of clearcutting in gentle terrain and near-complete removal of 

 the fiber indicate that this method will be most economical for residue harvesting. 

 This is true, of course, for almost any harvesting method comparisons. 



Methods and Equipment 



Figure 6 shows six systems for near-complete harvesting of relatively small-size 

 timber averaging 10-ft 3 piece size. Equipment for each system is shown in figure 7. 

 In a study of intensive utilization in lodgepole pine in Wyoming, merchantable and 

 nonmerchantable (residue) volumes were nearly equal. (This probably represents a 

 slightly less than normal volume of residue typical for lodgepole pine, but somewhat 

 greater than normal for most other species in the Rocky Mountain West.) 



Following is an example of the volume and classification of material from the 

 Wyoming study (Gardner and Hann 1972) . Description of unit 1 before and after 

 harvesting : 



Areas of unit (acres) - 16.8 



Average stand age - 168.7 



Average site index (50-yr base) - 43.7 



Volume/acre to 6-inch top of live standing trees (ft 3 ) - 5,912 

 Volume/acre to 6-inch top of dead standing trees (ft 3 ) - 1,014 

 Total volume/acre to 6-inch top (ft 3 ) - 6,926 (±621)* 

 Volume/acre of tree residuals** (ft 3 ) - 1,124(±205) 



Volume/acre of ground material <_ 3 inches in size (ft 3 ) - 1,820(±308) 

 Preharvest total volume/acre of (ft 3 ) - 9,870(±723) 



Postharvest volume/acre of ground material <^ 3 inches (ft 3 ) - 564 (±118) 

 * Figures in parentheses are 68-percent confidence intervals. 

 ** Tree residuals are the difference between total volume for trees 3.0 inches d.b.h. 

 and larger, and merchantable volume to a 6-inch top for trees 6.5 inches d.b.h. 

 and larger. 



Many combinations of equipment with different levels of mechanization could be 

 designed for harvesting 10 ft 3 (total tree volume, merchantable and nonmerchantable) 

 average timber size used in the simulation trials. Trials were therefore limited to 

 tests of representative equipment types that would either singularly perform subsystem 

 operations or combine them: felling, limbing, lopping, skidding, loading, hauling, 

 felling-bunching, felling-skidding, limbing-lopping, fel ling-limbing-lopping-bunching. 

 Other subsystem operations are performed as needed in each system shown in figure 7. 



Because simulation does not produce an optimum system, the trials in this report 

 are only to show possible methods of near-complete harvesting and their relative costs. 

 A list of equipment for each operation and estimated production data are given in 

 table 3. The special harvesting or processing equipment is shown in appendix A. 



