The promotion of electric energy production from solid biomass by the Austrian government has lead to a boom in the construction of new combined heat and power plants. The current total demand for wood chips in the research area for energy purposes is 70 400 m of loose volume chips per year. The expected increase in demand due to these new plants is more than 4 times greater than current demand: up to 302 700 m of loose volume per year. Even if the energy wood feedstock potential is satisfactory, the design of the supply chain is still unresolved. The aim of this study is to give decision-makers a base for further development. To accomplish this, we designed and tested four different supply scenarios: one for 9 plants and one for 16 plants. The scenarios were developed using a combination of geographic information systems (GIS) and linear programming methods. The results indicate that direct transport of solid fuel wood as round wood and chipping at the plant is the cheapest supply system with a resulting cost of 5.6–6.6 EUR/m loose. Using harvesting residues can only be recommended for large plants because of poor fuel quality. In this case, residues would be chipped at or near the landing, piled and transported via self-loading trucks at a cost between 8.4 and 9.1 EUR/m loose. In order to meet increasing demand and to ensure a continuous supply, especially during the winter and spring seasons it is necessary to optimize the supply chain by including storage terminals. However, using terminals and increased demand both lead to higher logistical costs. For example, if the total volume is handled via terminals, the average supply costs including storage will increase by 26%. Higher demand increases the costs by 24%.3 3 3 3

Purpose of Review: Winch-assist systems have seen rapid development, adoption, and implementation in many parts of the world in the past decade and can be considered one of the major recent innovations in steep terrain harvesting. Though a comparatively young topic, the literature around this topic has grown considerably during the last decade. This review summarizes the present body of literature on winch-assist systems and provides a comprehensive introduction to the topic. Recent Findings: The analysis showed that work safety in steep terrain harvesting operations has increased through winch-assist systems by removing workers from the many hazards of manual and motor-manual work. The extent of rutting, subsequent erosion, and soil densification after working with winch-assist systems was found to be similar to operations on gentle terrain or cable logging. Winch-assist harvesting is considered more productive than conventional steep terrain harvesting. While case studies provide indicative utilization and productivity values, a robust understanding of economic viability under varied stand and terrain conditions is not yet well established. Summary: Winch-assist is proving to be a robust, safe, and high-performance forest harvesting technology that has increased the operating range of ground-based, mechanized harvesting. It can help increase access to forest grounds in steep terrain that are previously considered economically marginal for forest management. Besides steep terrain, the potential benefits of winch-assist in reducing soil disturbance from ground-based equipment indicate that its operating range can also expand to gentle terrain where environmental impacts are of great concern due to wet or unstable soils. As the technology is relatively young and still evolving, there are many unknown social, environmental, and economic challenges and opportunities associated with the winch-assist technology. More research is certainly warranted.

In fully mechanized cut-to-length timber harvesting operations, the forwarder represents the limiting machine on steeper terrain in terms of trafficability. In order to operate also on steep terrain and on soft soils with low traction they can be equipped with traction winches. The objective of this study was to investigate setup time, develop a productivity model and calculate extraction costs for the winch-assisted forwarder John Deere 1110E. The productivity model is based on 75 observed cycles within 18 skid trails. The study was carried out in three different stands using detailed productivity and process analyses. Factors, which influence machine productivity, are piece volume (pv), inclination, distance during loading activities and extraction distance. With an average observed pv of 0.10 m³ and an average load volume of 9.25 m³, the winch-assisted forwarder reached a productivity of 13.7 m³/PSH₁₅, according to the developed model. By an annual utilization of 1,900 h and system costs for the entire machinery of 110.68 €/PSH₁₅, forwarding costs 8.06 €/m³. The detailed time and motion study showed different possibilities for mounting the cable depending on operation direction, terrain, passability through the stand and availability of the harvester. Average setup time for the cable operating downhill was 21.6 min, which additionally caused costs of 1.03 €/m³.

The objective of this case study was to develop and test a specific survey protocol for monitoring tensile forces for winch-assisted harvesters and forwarders with a mounted or integrated constant-pull capstan winch technology. Based on the designed survey protocol, the interactions between work phases, machine inclination, and tensile forces in typical work conditions were analysed. The established workflow, including equipment and the developed analysis routines, worked appropriately and smoothly. The working load on the cable during the study did not exceed 50% of the maximum breaking strength. A maximum tensile force peak at 56 kN was observed during delays for the forwarder, and a peak of 75.5 kN was observed for the harvester, both of which are still within the safe working load when considering a safety factor of two.

Controlling and organizing the complex forest-to-consumer supply chain of wood fuels is a challenging task, especially for the chipping and transport processes. Truck mounted chippers and transport trailer-trucks must be scheduled to minimize delay to be profitable. Job management within the supply chain, including machine activity based controlling, offers a new way to increase efficiency and productivity. However, detailed data are required to detect and analyze potential gaps and improve forest fuel supply. Generally, data regarding the wood fuel supply chain process are obtained from extensive time studies that are based on a specific process step. Although time studies can detect details during the production of forest fuels, they only describe certain time frames. Long-term data that are recorded during the entire year could encompass seasonal and short term effects. This study aims to monitor the forest fuel supply processes (semi-automated), specifically regarding time and fuel consumption. Large data sets were automatically and efficiently gathered with little effort by drivers and operators. Data were recorded with fleet management equipment for more than 14 months. Vehicle data, including GPS data, were logged at an interval of one minute. Data management was conducted in a pre-configured database that contained pre-defined reports and were run by the Institute of Forest Engineering, Vienna. Work step assignments were implemented with Structured Query Language (SQL)-routines by using the raw machine activities data and GPS. The chipping and transport activities of more than 240 loads were analyzed by focusing on fuel consumption, time needed and traffic. The average distance between chipping sites and plants was approximately 54 kilometers. Fuel consumption from transport reached 50 l/100 km. The chipping unit reached a productivity of 12.8 odt/PSH15 and had a fuel consumption of 58 liters per operating hour.