Large scale windthrow salvage logging is increasing in Central Europe because of the growth of severe atmospheric events due to global heating. Sustainable forest operations in these conditions are challenging in terms of both productivity performances and safety of the operations. Fully mechanized harvesting systems are the preferred solution on trafficable terrains and proper slopes. However, different work methods and logistic organization of the operations could largely change the overall performances. The study observed three harvesting sites based on fully mechanized cut-to-length systems and located in areas affected by the Vaia storm, which hit north-eastern Italy in October 2018. The objectives were to estimate forwarder productivity in salvage logging in difficult terrain and to identify significant variables affecting this productivity under real working conditions. Time and motion studies were carried out and covered 59.9 PMH 15 , for a total of 101 working cycles, extracting a total volume of 1277 m 3 of timber. Average time consumption for each site was 38.7, 42.2, and 25.1 PMH 15 with average productivity of 22.5, 18.5, and 29.4 m 3 /PMH 15 , respectively, for Sites A, B, and C. A total of seven explanatory variables significantly affected forwarder productivity. Average load volume, maximum machine inclination during loading, and number of logs positively affected the productivity. On the contrary, travel distance, load volume, maximum ground slope during moving and loading have a negative influence. With an average travel distance of 500 m, the productivity resulted 20.52, 16.31, and 23.03 m 3 /PMH 15 , respectively, for Sites A, B, and C. An increase of 200 m of travel distance causes a decrease in productivity of 6%.Forests 2020, 11, 341 2 of 14 or on (ii) passive management [6]. Active intervention strategies focus on rapid post-disturbance harvest and recovery of the economic value of the forest [7] in order to decrease the risk of a rapid reduction of the timber value due to reductions in wood quality [8], the risk of wildfires [9], and insect outbreaks [10].A common post-disturbance management approach is salvage logging [11,12] which consists of the widespread removal of damaged trees. Salvage logging benefits and drawbacks are widely discussed as it can have a negative effect on forests in terms of reducing biodiversity, increasing erosion, and reducing soil fertility [11]. Some authors report that salvage logging interventions must be planned considering the site-specific characteristics [13,14]. When salvage logging is appropriate to be applied, the most suitable technological solutions are those based on fully mechanized systems as these guarantee high productivity and above all a lower risk for operators as they work exclusively on the machines [15,16].In complex terrain and in mountain areas, with a low density of forest roads, the use of fully mechanized systems in salvage logging operations is difficult. In these conditions, the main system remains the semi-mechanized system based ...
Steep slope forest operations in Central Europe and in particular in the Alps are strongly related to the adoption of the cable-based harvesting system, even if innovative ground-based harvesting systems have been proposed in the last years. In this context, the present work aims to acquire a thorough knowledge of yarding technologies used by the logging companies of the central Italian Alps, to evaluate their professionality in steep slope forest operations, and to predict the potential diffusion of innovative steep slope harvesting systems in the area. The results show a large number of logging companies (106) working with cable-based systems and in particular with four different standing skyline yarding technologies. The analysis of professionality in using cable cranes shows big differences between the companies. In particular, it identifies a consistent group of companies with a highly mechanized machinery fleet and high skills and experience in steep slope forest operations. These enterprises evidence a still limited potential diffusion of the innovative ground-based harvesting systems in the area, even if it is theoretically possible according to the GIS analysis of morphology and forest road network.
Tree stability assessment is fundamental to preserve the safety of both people and goods. This topic attributes high relevance to cable-supported harvesting where trees and stumps are used as supporting and anchoring elements. In this case, the applied external loads are characterized by higher magnitude and dynamic amplification effects than the typical forces acting on trees (e.g., those derived from meteorological events). Consequently, due to the higher forces involved on cable-supported harvesting on relatively young trees used as supports and anchors, the risk of uprooting and stem failures is real. Numerous studies have been conducted on tree stability and the impact of the external loads has been positively linked to the consequent tree failures, in terms of root-plate overturning and stem breakages, or parasite-mediated wood decay involving the root system, thus giving a better understanding of how different trees species deal with such occurrences. This review aims to synthetize and examine the main aspects covered by research works available in literature that, directly or indirectly, might be helpful in clarifying the behavior of standing trees or tree stumps used as supports and anchors in cable-supported forest operations. Lastly, areas that lack research in this particular topic as well as consequent operating suggestions are highlighted in the conclusions.
In order to reduce greenhouse gas emissions, low emission or zero-emission technologies have been applied to light and heavyduty vehicles by adopting electric propulsion systems and battery energy storage. Hybrid cable yarders and electrical slack-pulling carriages could represent an opportunity to increase the energy efficiency of forestry operations leading to lower impact timber harvesting and economic savings thanks to reduced fuel consumption. However, given the limited experience with hybrid-electric systems applied to cable yarding operations, these assumptions remain uncertain. This study assessed an uphill cable yarding operation using a hybrid cable yarder and an active slack-pulling electric power carriage over thirty working days. A total of 915 work cycles on four different cable lines were analysed. Longterm monitoring using Can-BUS data and direct field observations were used to evaluate the total energy efficiency, total energy efficiency (%), and fuel consumption per unit of timber extracted (L/m3). The use of the electric-hybrid system with a 700 V supercapacitor to store the recovered energy made it possible to reduce the running time of the engine by about 38% of the total working time. However, only 35% to 41% of the Diesel-based mechanical energy was consumed by the mainline and haulback winches. Indeed, the remaining energy was consumed by the other winches of the cable line system (skyline, strawline winches and carriage recharging or breaking during outhaul) or dissipated by the system (e.g., by the haulback blocks). With reference to all work cycles, the highest net energy consumption occurred during the inhaulunload work element with a maximum of 1.15 kWh, consuming 70% of total net energy consumption to complete a work cycle. In contrast, lower energy consumption was recorded for lateral skid and outhaul, recording a maximum of 23% and 32% of the total net energy consumption, respectively. The estimated recovered energy, on average between the four cable lines, was 2.56 kWh. Therefore, the reduced fuel need was assessed to be approximately 730 L of fuel in the 212.5 PMH15 of observation, for a total emissions reduction of 1907 kg CO2 eq, 2.08 kg CO2 eq for each work cycle.
Noise is defined as an undesired sound that constitutes an unwarranted disturbance potentiality modifying animal behaviour or normal functioning. Forest operations commonly involve the use of equipment and machines that can produce noise and be a potential permanent or temporary disturbance for the wildlife. This study simulates noise propagation in a natural area generated during coppice stand harvesting by direct field noise measurements and the application of a specific GIS model. Two working phases were investigated: felling and yarding operations. Two potential systems were analyzed for the yarding operations: a) yarding by mobile cable yarder and b) skidding by tractor with a three point log grapple. The results are reported in terms of excess noise area for the third-octave bandwidths with the centre in 500 Hz, 1000 Hz and 2000 Hz. Felling by chainsaws presented the largest area where noise exceeds the ambient natural noise, while in the case of yarding, mobile cable yarding operations presented a smaller area of excess noise than skidding by tractor
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