This paper reviews the IUFRO lecture series, Forest Roads: regional perspectives from around the world. In reviewing the presentations in this series, we found that regional factors such as geology, historic climate (glaciation), current climate, topography, and ownership strongly affect forest road networks. In addition to these regional factors, it appears that historic land use affects road design and construction. We define three road classifications: pioneer, mature, and plantation. In a pioneer road network, there is an existing forest resource and no established road network. A pioneer road network strongly reflects the current regulatory environment, current harvesting systems, and regional factors. A plantation road network occurs where there is a land use change, often from agriculture to forestry, and often growing non-native species. Plantation road networks evolve from existing rudimentary roads to road networks planned specifically for a well-defined forest resource. The plantation road network does reflect the existing regulations and harvesting systems; however, it does exist in a more constrained system that is defined by the existing roads and the boundaries of the planted forest. Mature forest road networks have evolved over centuries and incorporate historic and current land use, evolving regulations and technology, and are often interconnected with public roads. Responses specific to these road classes include a pioneer road network using brush mats to help support the subgrade, a plantation road network applying an optimized design, and a mature road network using pavement as the road surface.

For a limited set of conditions we have shown that recovering braking energy from log trucks descending from high elevation stands to lower elevation manufacturing facilities can reduce the size of the battery required to run a log truck. Adding level highway hauls after descending from the higher elevation stands quickly increases the required battery capacity. The effect of conversion efficiency on the required battery capacity is correlated with the change in elevation along the haul route. At a conversion efficiency of 100% (battery-to-wheels and wheels-to-battery), the cumulative battery usage on the base profile (elevation factor = 1.0) is only one-half of what it would have been compared to a level road of the same horizontal length (elevation factor = 0.0). When the conversion efficiency is set to 60%, the cumulative battery usage for the base profile would be the same as if the truck had been on a level road of the same horizontal distance. For the actual haul route considered in this paper the minimum battery mass required for a single round trip is limited by peak power requirements; however, energy storage becomes limiting as longer level highway haul sections are added.

This paper presents a solution for a three-stump anchor system using a continuous bridle and assuming frictionless blocks. This solution is unique in that the location of the bridle block is not known a priori. A particle swarm optimization was used to estimate the three coordinates of the bridle block and the tension in the bridle. A method employing trilateration was developed to locate the known points in the three-stump anchor system, the advantage to using this method is that only distances between known points need to be measured in the field (angles are not required). For two of the field cases, the ratio of skyline tension to bridle tension was close to the maximum of 6 (bridal tension reduction factor) that could be achieved given the three-stump anchor system, and the other case had a ratio of 4. It was found for shorter bridle lengths the three-stump anchor system is more sensitive to how in lead the stumps are with the skyline. For three-stump anchor systems, the bridle tension is more strongly controlled by the location of the two outside stumps, and it is relatively insensitive to the location of the middle stump.