The design, evaluation and control of harvesting systems in a problem of considerable importance in the forest products industry. Modeling of timber harvesting system include considerations such as production rates, equipment breakdown, fixed and variable costs material flow and scheduling priorities. The resulting mathematical analysis is not computationally feasible. Computer simulation can be effectively used to accurately represent complex systems such as timber harvesting, that are affected by numerous variables. The research reported in this paper developed as simulation model for analyzing the entire logging operation (tree-to mill) in the forest products industry.