The Examination of Cost-effective Weeding Schedules Using Monte Carlo Simulation:

A Case Study of the Sugi (Cryptomeria japonica) Stand in Takakuma Experimental Forest of Kagoshima University

Abstract

This study identified the cost-effective weeding schedules for reducing weeding cost. First, we used a Monte Carlo method to simulate 7-year-old sugi (Cryptomeria Japonica) mean height and cumulative weeding operation time under different combinations of weeding timing and frequency from 0 to 6 times after planting. Then, we calculated operation time per sugi mean height to express cost-effectiveness. Moreover, to evaluate the stability of the cost-effectiveness, we calculated coefficient of variation for sugi mean height, cumulative operation time and operation time per sugi height. Each coefficient of variation was lower when weeding frequency was equal to or more than three times. The operation time per sugi height decreased when weeding was conducted in the first or second year after planting. We conclude that the three-treatment weeding frequency including the first- or second-year weeding is more effective weeding for the reduction of weeding costs.