Simulating differences between forwarding short and normal-length timber

Abstract

Normal log lengths in Norway are 3-6 m (NL), but occasionally there is a demand for short timber with a 2.5 m log length (ST). There are concerns that ST could reduce the forwarders' productivity. Six type stands were created based on harvester data. Different assortment distributions, conditions, and forwarders were simulated in each type stand. It was found that an additional ST assortment almost always decreased productivity (from -15.5 to +4%). Increased forwarding distance (m), more difficult driving conditions, and increased log concentration [m3.(100 m strip road)-1] decreased the productivity difference between sites with ST and NL and sites with only NL. Increased forwarder size increased the productivity difference between sites with ST and NL and sites with only NL. It is possible to load two stacks of ST on some forwarders. Such loading was more productive than loading one stack on longer forwarding distances, while the opposite was the case on short distances. However, loading two stacks of ST can lead to overloading.

Keywords

• analysis of covariance (ancova)
• clear cutting
• comparative study
• computer simulations
• relative difference
• terrain transportation