عنوان مقاله [English]
Tree felling is the most important component among tree harvesting which consists of cutting, limbing and bucking. This research was carried out in two compartments in Namkhaneh district of Kheyrud Forest. The Objective of this study were the time study of conventional and directional tree felling operation, estimation of productivity and costs of chainsaw for both conventional and directional methods, and development of regression model. Factors affecting on bucking time regression model were DBH of harvested tree and inter-tree distance for conventional method and DBH of harvested tree and direct of felling regarding to the lay directional felling. The hourly production of conventional tree felling with and without delay time was 46.4 and 65.6 m3/h, respectively. However, in directional felling method, the hourly productions with and without delay time were 44.4 m3/h and 59.1 m3/h, respectively. Productivity of chainsaw felling increased related to tree DBH as power for both conventional and directional felling method. The cost of felling was increased as simple exponential equation when DBH of harvested tree decreased for both conventional and directional felling method. Result indicates that the directional felling was more expensive than conventional felling.