Capability and Costs of Motor-manual Delimbing and Bucking (Case Study: Kheyrud Forest)

Tree felling، delimbing and bucking includes all activities undertaken to fell standing trees and prepare them for extraction. The study was conducted in Gorazbon district in the Hyrcanian forests. In this study، the objectives were to discover the special characteristics in the time consumption of manual tree delimbing and bucking، productivity and costs، and develop regression model. The continuous time study was conducted with professional operators for chain-saw delimbing and bucking and the cycles were broken down into time elements. Tree delimbing time of working crew is the most time-consuming element in delimbing and bucking، followed by bucking and rest and meal time. The operational and personal delay is the most time-consuming delay time in tree delimbing and bucking. Result showed that time consumption for delimbing and bucking was increased with increasing diameter. Labor costs accounted for 37% of the hourly cost while only 1. 5% was related to machine cost. A significant linear relationship was found between delimbing and bucking cycle time and diameter. Productivity of chainsaw delimbing and bucking was increasing related to tree DBH as power. The costs of chainsaw delimbing and bucking with and without delay time were 203710 and 179796 Rial/m3، respectively. The cost of delimbing and bucking was increased as simple exponential equation when DBH of harvested tree was decreased. However، the unit delimbing and bucking cost for chainsaw operation decreased as tree size increased. Total delimbing and bucking cycle time without delay averaged 25. 31 minutes and with delay time were averaged 22. 34 minutes.