Example 2. 



Assume a thin stand has large timber on moderately steep slopes where average skidding 

 distances run up to 600 feet. Assume further that high-lead equipment is not available. The 

 variables for this situation: area density, 5 MBF/acre; skidding distance, 600 feet; slope, 40 

 percent; and tree size, 4 logs/MBF. Using the same procedure as you did in Example 1, you 

 would derive the following: 



Skidding type 



Cost 





($/MBF) 



Crawler tractor, 25-40 DBHP 



5.89* 



Crawler tractor, 41-60 DBHP 



4.49* 



Crawler tractor, 61-80 DBHP 



2.90* 



Crawler tractor, 110-130 DBHP 



3.68 



Rubber-tired vehicle, 55-80 BHP 



2.88* 



Rubber -tired vehicle, 81-117 BHP 



4.09* 



High- lead, portable tower 



Not available 



Idaho jammer 



Not applicable 



Shovel (w /tongs) 



Not applicable 



Extrapolated values 



As noted earlier, shovel logging is limited to a maximum skidding distance of 150 feet and 

 couldn't be used in this situation. Furthermore, we didn't view the use of the Idaho jammer 

 method as being applicable because among the operations studied none were for skidding dis- 

 tances of over 400 feet. This is not to say that the Idaho jammer can't be used for skidding 

 longer distances. 



Although the skidding cost for the 55-80 BHP rubber-tired vehicle is an extrapolation, it 

 does represent a savings of at least 20 percent over the lowest estimated cost ($3.68 for the 

 110-130 DBHP crawler tractor). The cost for the 61-80 DBHP crawler tractor also represents 

 savings of at least 20 percent; thus, for all practical purposes it would be as economical to use 

 the crawler tractor as it would be to use the smaller rubber-tired skidder. Your choice would 

 rank as follows: (1) rubber-tired vehicle, 55-80 BHP, (2) crawler tractor, 61-80 DBHP, 

 (3) crawler tractor, 110-130 DBHP, (4) rubber-tired vehicle, 81-117 BHP, etc. The level of 

 20 percent is set arbitrarily as a guide and may be changed at the discretion of the operator. 



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