Estimating the economic life of forest machineryusing the cumulative cost model and cost minimizationmodel in Iranian Caspian forests

摘要

This study was conducted in order to estimate the economic life of two models of rubber-tired skidders, namelyTimberjack 450C and HSM 904, in Iranian Caspian forests. The total annual costs and average cumulative cost ofskidders were calculated by life-cycle costing analysis. The economic life of the machines was estimated by boththe cumulative cost model and cost minimization model. The results indicated that the economic life of Timberjack450C and HSM 904 is 7,700 h (at the end of the 11th year) and 15,300 h (at the end of the 17th year), respectively,using the cost minimization model. Furthermore, the results indicated that the economic life of Timberjack 450Cand HSM 904 is 9,100 h (at the end of the 13th year) and 11,900 h (at the end of the 21st year), respectively, usingthe cumulative cost model. The cumulative cost model estimated the economic life of skidders longer than the costminimization model.