Articles by Raffaele Spinelli

The use of modern multi-functional forestry machines has already been associated with central nervous system fatigue induced by high mental workload. As these machines are being used under increasingly difficult terrain conditions, further knowledge is required on the expected aggravation of operators’ mental workload, so that suitable work/rest schedules can be developed. Within such a context, the aim of this study was to gauge aggravations of mental workload derived from increasing slope gradient. Measurements of eye activity were obtained from a representative harvester operator working in corridors with the following mean inclinations: 9%, 23% and 47%. The duration, frequency and trajectory of eye movements were used to determine the harvester operator’s mental workload, on the assumption that worsening work conditions would be reflected by increased eyeball activity. The number of fixations during the performance of all tasks increased with the increasing slope gradient. Similarly, fixation duration increased with slope gradient. The mean duration of saccades when working on a 23% slope was 5% shorter compared to work under a 9% gradient. A further significant shortening of saccade duration (~22%) occurred when working on a 47% slope. The good match between eye activity cycles and work cycles, visible especially on steep slopes, indicates that mental workload is related to work conditions. Overall, operating a forest harvester on steep slopes results in a greatly increased mental workload and calls for suitable rest schedules.

• Szewczyk, University of Agriculture in Krakow; al. 29 Listopada 46, 31-425 Kraków, Poland E-mail: rlszewcz@cyf-kr.edu.pl
• Spinelli, National Research Council of Italy, Firenze, via Madonna del Piano, 10 50019 – Sesto Fiorentino, Italy E-mail: spinelli@ivalsa.cnr.it
• Magagnotti, National Research Council of Italy, Firenze, via Madonna del Piano, 10 50019 – Sesto Fiorentino, Italy E-mail: natascia.magagnotti@ibe.cnr.it
• Tylek, University of Agriculture in Krakow; al. 29 Listopada 46, 31-425 Kraków, Poland E-mail: rltylek@cyf-kr.edu.pl
• Sowa, University of Agriculture in Krakow; al. 29 Listopada 46, 31-425 Kraków, Poland E-mail: janusz.sowa@urk.edu.pl
• Rudy, State Forests, Biłgoraj Forest District, ul. Zamojska 96, 23-400 Biłgoraj, Poland E-mail: rudy.piotrek@o2.pl
• Gaj-Gielarowiec, State Forests, Barycz Forest District, Barycz 69, 26-200 Końskie, Poland E-mail: dominika.gaj@gmail.com

Cable yarding is a general solution for load handling on sites not accessible to ground-based machinery, and is typically associated with steep terrain. On flat terrain, such conditions can primarily be found on soft or wet soils, most frequently encountered in Central and Northern European countries. Today, changed environmental and market conditions may offer an unprecedented opportunity to the actual implementation of cable yarding on flat terrain in commercial operations. The study goal was to collect cable yarder manufacturers experience regarding the use and adaption of cable yarding technology on flat terrain. European manufacturers of cable yarding technology were interviewed about customer experience, particular challenges, adaptation potential, future potential and main hurdles for the expansion of cable yarding on flat terrain. Almost all manufacturers have received requests for flat-terrain yarding technology solutions, primarily from Germany. Temporal or permanent inaccessibility, regulatory or environmental reasons were the most frequent motivation for considering cable yarding technology. Installation was considered particularly challenging (clearance, stable anchoring). Potential adaptations included higher towers, artificial anchors, mechanized bunching before extraction and un-guyed yarder-systems. An artificial, highly mobile, self-anchoring tail spar was considered the most useful adaptation. While concerned about limited profitability and qualified labour shortage, most manufacturers demonstrated a positive or neutral view concerning the expansion of cable yarding on flat terrain. However, cable yarding is not considered to be cost-competitive wherever ground-based systems can be employed and cable yarding is not subsidized.

• Erber, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter Jordan Strasse 82, 1190 Vienna, Austria https://orcid.org/0000-0003-1606-5258 E-mail: gernot.erber@boku.ac.at
• Spinelli, CNR-IBE Consiglio Nazionale delle Ricerche-Istituto per la BioEconomia, Via Madonna del Piano 10, Sesto Fiorentino, Firenze, I-50019, Italy; AFORA, University of the Sunshine Coast, Locked Bag 4, Maroochydore, QLD, Australia https://orcid.org/0000-0001-9545-1004 E-mail: spinelli@ivalsa.cnr.it

Industrial chipping is becoming increasingly popular, as the result of a growing demand for woody biomass. Industrial chippers are large, powerful machines that generate much noise and vibration. This study explored some factors that may affect exposure to noise and vibration, namely: feedstock type (branches vs. logs), work station characteristics (truck cab vs. separate cab) and knife wear (new knives vs. blunt knives). Exposure to noise was significantly affected by all three factors, and it was higher for branch feedstock, separate cabs and blunt knives. The higher exposure levels recorded for the separate cab were especially insidious, because they were below and above the hearing threshold and would elude immediate perception. Exposure to whole-body vibration (WBV) was significantly higher for branch feedstock and for the separate cab. Knife wear seemed to determine an increase in WBV, but this effect had no statistical significance and the result could not be taken as conclusive. Among the three factors studied, work station characteristics had the strongest effect. Further studies may extend the comparison to a wider range of options, as well as explore the use of exposure variation for machine diagnostics.

• Anton, University of Ljubljana, Dept. of Forestry and Renewable Resources, Večna pot 83, 1000 Ljubljana, Slovenia E-mail: anton.poje@bf.uni-lj.si
• Spinelli, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy; AFORA, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland, 4558 Australia http://orcid.org/0000-0001-9545-1004 E-mail: spinelli@ivalsa.cnr.it
• Magagnotti, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy; AFORA, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland, 4558 Australia E-mail: magagnotti@ivalsa.cnr.it
• Mihelic, University of Ljubljana, Dept. of Forestry and Renewable Resources, Večna pot 83, 1000 Ljubljana, Slovenia E-mail: matevz.mihelic@bf.uni-lj.si

Chain flail delimbing and debarking may improve value recovery from small tree harvests, without renouncing the benefits of multi-tree processing. The technology is mature and capable of excellent performance, which has been documented in many benchmark studies. This paper offers new insights into the relationship between the performance of chain flail delimbing and debarking and such factors as tree volume, load volume, tree form and bark-wood bond strength (BWBS). The study was conducted in Chile, during the commercial harvesting of a Eucalyptus globulus Labill. plantation. In an observational study, researchers collected production data from over 780 work cycles, and work quality data from over 1000 individual trees. The analysis of these data shows that productivity is affected primarily by load volume. Work quality is affected by BWBS and by the number of trees in a load. Work quality degrades with increasing BWBS and tree number, since more trees tend to shield each other. Tree form has no effect on either productivity or work quality. Regression and probability functions are provided, and can be used for predictive purposes when trying to optimize current operations or to prospect the introduction of chain flail technology to new work environments.

• McEwan, Postgraduate Forest Programme, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20 Hatfield, Pretoria, 0028, South Africa E-mail: Andrew.McEwan@nmmu.ac.za
• Brink, Postgraduate Forest Programme, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20 Hatfield, Pretoria, 0028, South Africa E-mail: michal@cmo.co.za
• Spinelli, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (FI), Italy http://orcid.org/0000-0001-9545-1004 E-mail: spinelli@ivalsa.cnr.it

A time study was conducted to determine whether stem crowding had any impact on harvester productivity in Eucalyptus grandis stands. This represents an important element when trying to balance the advantages and disadvantages of coppice management in fast growing plantations designated for mechanized harvesting (i.e. machine felling, delimbing, debarking and cross-cutting). The study material consisted of 446 coppice stems, half of which grew as single stems per stool and half as double stems per stool as a result of different coppice reduction strategies. The dataset was balanced and randomized, with both subsets replicating exactly the same stem size distribution and the single and double stems alternating randomly. Harvester productivity ranged between 6 and 50 m³ under bark per productive machine hour, following the variation of tree diameter from 10 to 40 cm at breast height (1.37 m according to South African standards). Regression analysis indicated that both tree size and stem crowding (e.g. one or two stems per stool) had a significant effect on harvester productivity, which increased with stem size and decreased with stem crowding. However, operator experience may overcome the effect of stem crowding, which was not significant when the harvester was manned by a highly experienced operator. In any case, the effect of stem size was much greater than that of stem crowding, which resulted in a cost difference of less than 10%. However, this figure excludes the possible effects of stem crowding on volume recovery and stem development, which should be addressed in the future.

• McEwan, Nelson Mandela Metropolitan University – George Campus, Saasveld, 6529, George, South Africa E-mail: Andrew.McEwan@nmmu.ac.za
• Magagnotti, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (FI), Italy E-mail: magagnotti@ivalsa.cnr.it
• Spinelli, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it

The present research focuses on the productivity of energy wood chipping operations at several sites in Italy. The aim was to assess the productivity and specifically the effect attributed to the operator in the chipping of wood biomass. The research included 172 trials involving 67 operators across the country that were analysed using a mixed model approach, in order to assess productivity, and to isolate the operator effect from other potential variables. The model was constructed using different predictors aiming to explain the variability due to the machines and the raw-materials. The final model included the average piece weight of raw material chipped as well as the power of the machine. The coefficients of determination (R²) were 0.76 for the fixed part of the model, and 0.88 when the effects due to the operators were included. The operators’ performance compared to their peers was established, and it was compared to a subjective classification based on the operator’s previous experience. The results of this study can help to the planning and logistics of raw material supply for bioenergy, as well as to a more effective training of future forest operators.

• Mola-Yudego, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland; NIBIO Norwegian Institute of Bioeconomy Research, P.O. Box 115, 1431 Ås, Norway http://orcid.org/0000-0003-0286-0170 E-mail: blas.mola@uef.fi
• Picchi, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy E-mail: picchi@ivalsa.cnr.it
• Röser, Forest Feedstocks Group, FPInnovations, Vancouver, British Columbia, Canada E-mail: dominik.roser@fpinnovations.ca
• Spinelli, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy E-mail: spinelli@ivalsa.cnr.it

• Spinelli, CNR IVALSA,Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it
• Lombardini, CNR IVALSA,Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: lombardini@ivalsa.cnr.it
• Magagnotti, CNR IVALSA,Via Biasi 75, S. Michele all’Adige (TN), Italy E-mail: magagnotti@ivalsa.cnr.it

• Spinelli, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it
• Cavallo, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: e.cavallo@imamoter.cnr.it
• Eliasson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: lars.eliasson@skogforsk.se
• Facello, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: a.facello@ima.to.cnr.it

• Costa, CRA ING, Monterotondo Scalo (Roma), Italy E-mail: cc@nn.it
• Menesatti, CRA ING, Monterotondo Scalo (Roma), Italy E-mail: pm@nn.it
• Spinelli, CNR IVALSA, Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it

• Spinelli, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it
• Magagnotti, CNR IVALSA, Via Biasi 75, S. Michele all’Adige (TN), Italy E-mail: nm@nn.it
• Paletto, CNR IMAMOTER, Strada delle Cacce 73, Torino, Italy E-mail: gp@nn.it
• Preti, CNR IMAMOTER, Strada delle Cacce 73, Torino, Italy E-mail: cp@nn.it

• Spinelli, CNR/IVALSA, Via Madonna del Piano - Palazzo F, I-50019 Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it
• Nati, CNR/IVALSA, Via Madonna del Piano - Palazzo F, I-50019 Sesto Fiorentino (FI), Italy E-mail: cn@nn.it
• Magagnotti, CNR/IVALSA, Via Madonna del Piano - Palazzo F, I-50019 Sesto Fiorentino (FI), Italy E-mail: nm@nn.it

• Spinelli, CNR - Timber and Tree Institute, Via Madonna del Piano - Pal. F, 50019 Sesto Fiorentino, Italy; University College Dublin, Ireland E-mail: spinelli@ivalsa.cnr.it
• Owende, Dept. of Agricultural and Food Engineering, University College Dublin, Earlsfort Terrace, Dublin 2, Ireland E-mail: pmoo@nn.ie
• Ward, Dept. of Agricultural and Food Engineering, University College Dublin, Earlsfort Terrace, Dublin 2, Ireland E-mail: smw@nn.ie
• Tornero, Servicios Forestales SA, Ctra. SE-184 Km 0.63, E-41970 Santiponce, Sevilla, Spain E-mail: mt@nn.es