C. Kevin Lyons

Decarbonizing Oregon’s heavy-duty trucking sector, which accounts for 24% of the state’s transportation emissions, is essential for meeting carbon reduction targets. Drop-in fuels such as renewable diesel, biodiesel, and synthetic fuels provide an immediate and effective solution, reducing emissions by up to 80% while utilizing the existing diesel infrastructure. In 2023, Oregon’s heavy-duty trucks consumed 450 million gallons of diesel, with drop-in fuels making up 15% of the fuel mix. Renewable diesel, which is growing at a rate of 30% annually, accounted for 10% of this volume, thanks to incentives from Oregon’s Clean Fuels Program. By 2030, drop-in fuels could capture 40% of the market, reducing CO₂ emissions by 3.5 million metric tons annually, assuming continued policy support and advancements in feedstock sourcing. Meeting the projected demand of 200 million gallons annually and securing sustainable feedstock remain critical challenges. Advances in synthetic fuels, like Power-to-Liquids (PtL) from renewable energy, may further contribute to decarbonization, with costs expected to decrease by 20% over the next decade. Oregon aims for a 50% reduction in emissions from heavy-duty trucks by 2050, using a mix of drop-in fuels and emerging technologies. While hydrogen fuel cells and electric trucks face challenges, innovations in infrastructure and vehicle design will be key to the success of Oregon’s long-term decarbonization strategy.

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.

This paper developed six cable logging incident scenarios that were modeled in a simulated environment, and conducted a pilot study in the Pacific Northwest to assess the potential for collecting worker risk assessment data. All the subjects in the pilot study reported that they understood the simulated incidents, and they were able to move around in the simulation to see what they needed. When reporting management requiring conditions (MRC) before performing the simulated task, the subjects consistently identified the first main MRC; however, there was variation in reporting the second main MRC. The results from the pilot study indicate that the simulations effectively modeled the spatial aspects of the incidents; however, the simulations lacked avatars to represent people in the simulations and this may have limited the ability to include cognitive aspects such as communication. Variation in the severity assigned by the subjects to the MRC, and to the unexpected events, revealed important differences in risk sensitivity between the subjects, and the importance of experiential learning in a safe environment when considering energized systems.

The standing skyline continues to be a common cable logging configuration. In payload analysis it is usually assumed that the tagline (line connecting the logs to the carriage) length is held constant while yarding a turn up the skyline corridor. We show this assumption severely limits the skyline load-carrying capacity for skylines operating with partial suspension. We suggest that smart carriage technology could markedly increase the log load capacity through the use of a variable length tagline, and thus logging productivity. A methodology for estimating the log load capacity for a standing skyline with variable tagline length is presented. We illustrate that increases of 30–40 percent in log load are possible with a variable length tagline.

Cable tensile forces in winch-assist harvesting have been investigated in order to assess the safety concerns of the technology. However, the literature is lacking, particularly in regards to the impact of winch design. In this study, a Summit Winch Assist tethering a feller-director on ground slopes up to 77% was monitored for four days. The cable tensile forces were simultaneously recorded at the harvesting and anchor machine at a frequency of 100 Hz. Cameras and GNSS devices enabled a time study of the operations and the recording of machine positions. Winch functionality and design were disclosed by the manufacturer and used for the interpretation of the results. The cable tensile forces reached 296 kN at the harvesting machine and 260 kN at the anchor machine. The slow negotiation of obstacles while moving downhill recorded the highest peaks, mainly due to threshold settings of the winch in the brake system activation. Lower but significant peaks were also recorded during stationary work tasks. The peaks, however, were limited to a few events and never exceeded the endurance limit of the cable. Overall, the study confirmed recent findings in cable tensile force analysis of active winch-assist operations and provided evidence of the underlaying mechanisms that contribute to cable tensile forces.

This article examines the performance of an existing log truck cab guard subject to impact from the load of logs shifting forward during sudden truck deceleration, and considers modifications to the cab guard to reduce the effect of impact. It was found that the logs impacted the existing cab guard with a load sufficient to reach the design displacement of 0.25 m and to exceed the yield stress in the foot and in the gusset for log truck decelerations greater than 32.5 m/s². Increasing the cross section of the cab guard foot reduces the maximum stress found in the foot; however, this resulted in the maximum stress in the gusset increasing from the original design. Increasing the gusset thickness resulted in a slight decrease in the maximum stress found in the gusset, with little change in the maximum stress found in the foot. Increasing the yield stress of the steel did not change the stress distribution; however, this did result in the maximum stress found in the foot being below the new yield stress. Adding an energy absorbing pad to the cab guard improved all the performance metrics resulting in the maximum stress in the foot being well below the original yield stress, reducing the maximum stress in the gusset to near the yield stress, and reducing the displacement by almost a third.

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.