An Economical Transportation Plan for Forest Products Using a Computer-Aided Model

The paper presents a computerized model for finding the single most economical landing location for ground-based timber harvesting and finding the least cost road path from the selected landing point to the existing off-road. The model uses raster-based GIS data and considers multiple design factors influencing the optimal landing location. Terrain conditions, the volume of stock distribution, downhill and uphill skidding directions, and distance to the existing road were the influencing design factors in the model. Three approaches were adopted for finding a landing location within three harvest units. In the first approach, a preliminary process evaluated all cells of a 20m_20m network within the harvest units and determined the candidate landing cells with the largest gentle slope (<10%) area. In the second and third approaches, the points on a 50m_50m mesh grid and the harvest units’ centroids were assumed as candidate landings, respectively. The sum of skidding, road construction, and hauling costs was as total harvesting costs. Results indicated that the distance to the existing roads and the access direction from the existing road to the candidate landings could effectively limit the choice options for landing location. Results of feeding a penalized cost estimation model as an objective function to the modified Dijkstra’s shortest path algorithm led to planning the road alignments with the least expected excavation and soil disturbance. Results also showed that the optimal landings could ensure the least total harvesting cost within the harvest unit.