3. Productivity of equipment = function of: 



a. Sidehill slope 



b. Number of logs per turn 



c. Size of the logs (in logs/MBF^) 



d. Distance skidded to road 



The above variables are summarized in table 1, showing the functional relation- 

 ship and cost factors. The syinbols used for each variable are also given. 



The optimization of log removal required the consideration of two general cases 

 (fig. 1). The first oase involves harvesting a stand of timber that is accessible by 

 contour work roads extending from an existing primary road (in the Rocky Mountain 

 area, this is usually a climbing road), and the second case involves the construction 

 of work roads that switch back and forth across the area to be harvested. 



The first case is the simplest because the cost of switchbacks doesn't need to be 

 considered in the total cost equation. The seaond aassy which includes switchbacks, 

 will be used in this analysis. When the model is used for the nonswitchback case, this 

 cost factor can be removed. 



The development of the eight cost equations will not be discussed here because of 

 the lengthy details and space required for complete understanding. However, these 

 equations are listed below. All costs are converted to a common unit of dollars per 

 ore thousand board feet ($/MBF) . All distance measurements are in horizontal units. 

 Values for productivity of construction equipment and productivity coefficients were 

 derived from past records and studies. 



Cost Equations 



Move-in, construction 

 Road planning and layout 

 Road construction 

 Switchback construction 



Landing construction 

 Move- in, skidding 

 Setup, skidding 

 Skidding 



= Nc/AV 



= 43,560 Dm/Pm Fm XV 



= 43,560 Dc Hr/Pc FVX 



^ 43,560 Dc Hr 



4 1 



Pc VXF Zb + X{ (S2/Mx2)-1 



200 Dc Hr 

 * Pc F 



= 43,560 Dc Hl/Pc VXY 



= Ns/AV 



6 



= 43,560 Ds Sp/Zs VX 



C = [Dc/Ps Vc] [ai+a2S+a3VcLv+ai, 

 (dav.)] 



MBF = 1,000 board-foot measure, log scale. 



6 



