A Simulation Method for Estimating Growth Losses Caused by Strip Roads

The paper presents and tests a method for comparing real thinning with strip roads and a simulated selective thinning pattern without strip roads in the same tree stand. The simulation method includes growth models for single trees, and a computer program for carrying out different selective thinning patterns. Simulation proved to be a more reliable method than the simple comparison between the stand growth on 15 m wide zones including and excluding the strip road. The method reduces the effects of random and systematic differences, especially on the small experimental plots. The material of young and middle-aged Norway spruce stands (19 plots) showed that the growth loss is 0-10% during the first ten years, depending on the width of the strip road and the density of the stand.