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ŠUMARSKI LIST 7-8/2017 str. 48     <-- 48 -->        PDF

While one would generate tremendous number of strategies, we selected a reasonable one to test and understand operational planning toward a better solution. Maximum timber production was the main forest management goal in İkisu PU. Therefore, a planning strategy was developed with harvesting volume and forestation area flow constraints considering periods and solved with LINDO™ software. The following mathematical equations are used to build the model.
Objective Functions:
                                               Zmax= H                                (Eq. 1)
Subject to:
                                                                                              (Eq. 2)
                                                                                              (Eq. 3)
                                                                                             (Eq. 4)
                                                                                             (Eq. 5)
                                                                                              (Eq. 6)
                                                                                             (Eq. 7)
                                                                                             (Eq. 8)
:  Stand area i, regenerated in period j (ha)
:  Number of stands (i=1 to 129).
:  Silvicultural treatment options (j=1 to 5)
:  Amount of one ha timber production value of stand i cut in period j (m3)
:  Distance of stand i to the nearest forest road that regenerated in the first period (m)
:  Total harvesting volume (m3)
:  Stand area i (ha)
:  Total harvesting volume in period j (m3)
:  Final felling area in period j (ha)
:  Forestation area in period j (ha)
:  Permitted total distance in the first period (m)
:  The change rate between periods (10%)
Operational Planning Stage – Faza operativnog planiranja
In order to achieve the integration of different timber extraction systems in harvest planning with a number of different scenario analyses considering time, quantity, economics and environment, a broad range of information was required. Harvest areas have different conditions such as; ground slope, volume, timber extraction direction or distance. In the meantime, the machines have different capacities, costs or efficiencies. Moreover, the planning of harvesting operations requires the consideration of restrictions or limitations of interested enterprise. Therefore, decision making techniques should be used, taking into consideration the different performance functions such as net income, time or timber loss as well as terrain or machinery conditions in the operational planning process (Acar et al., 2000; Bredström et al., 2010; Çalışkan and Karahalil, 2015). In this way, appropriate timber extraction method could be selected, needed to perform the operations at each harvest area or compartment to reach the desired goals under different restrictions.
Some factors such as working direction, slope limits, efficiency, costs or operation distance were found to be different