prilagođeno pretraživanje po punom tekstu

ŠUMARSKI LIST 7-8/2017 str. 51     <-- 51 -->        PDF

Similarly, STR2 has the same objective as maximizing net profit. However, STR2 has constraints as 2000 working hours for the selected timber extraction systems as small size, cable cranes, medium size cable cranes and sledge yarders respectively. On the other hand, STR3 minimizes the total damage from timber extraction activities at the end of the period with 2000 working hour constraints on small size, cable cranes, medium size cable cranes and sledge yarders.
Approximately 68,728 m3 annual allowable cut was determined for the first planning period. The outputs of the model were given in Table 4. While the allowable cut and regeneration area followed an increasing pattern, on the other hand, forestation was gradually decreased because of the 10% flow constraints. As the other periods were not considered in terms of limiting the distance from the harvesting areas to the nearest forest road, „distance to forest road” values are unavailable for the further periods. Spatial locations of the stands subject to regeneration or thinning activities in the first period in İkisu was also given in Figure 3.
When all operational planning strategies are considered, the highest profit was obtained from STR1 followed by STR2, as 6.4 million € and 6.3 million € respectively. STR3 and STR2 yielded the highest cost, as 501.6 thousand € and 298.1 thousand €. Strategies that generated the lowest time are STR1 (15,057 hours) and STR2 (19,055 hours). Total timber loss was the minimum in STR1 (952.9 m3) followed by STR2 (1,697.8 m3), and finally maximum total damage was yielded by STR2 as 91.77 (Table 5).
Planning strategies were also compared to each other in terms of time consumption, considering each timber extraction systems at the end of the planning period. These results indicated that STR2 and STR3 used the upper limits in both cable cranes and sledge yarder. On the other hand, spent time causes fluctuation in man power, animal power and skidder in a wide range in relation to objective function and constraints (Table 6).
Table 6 shows total spent time outputs considering each timber extraction system. Therefore, 1,451 hours used as