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The woody biomass resulting from pruning and replacement operations of different orchards can become fuel in biomass-fired power plants. The technologies currently used, borrowed from not agricultural specific solutions and often derived from the forestry sector, offer benefits on machine performance but, on the other hand, do not allow the product obtained to meet the quality and cleanliness requirements of biopower plants. The present work aims to examine and match the types of orchards and management with the available explant and biomass management technologies, highlighting advantages and limitations under the various aspects of the complete logistic chain: harvesting, transporting and chipping. The main novelty is the possibility of applying specific technologies to optimize the costs and the quality of the end product. The data obtained show specific correlations between the mandatory compliance of the end product quality and commercial cleanliness standards, the type of orchard, and the used technique. Furthermore, the working times of the different collection lines do not differ significantly, opening issues on the possibility of setting up targeted interventions for fruit tree explantation and the subsequent woody biomass management., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 262-265

Partendo dai risultati di uno studio basato sui questionari di valutazione dei corsi di formazione per operatori forestali svolti in Piemonte in 8 anni, si fanno alcune considerazioni sull'opportunità di organizzare tali corsi coinvolgendo maggiormente il mondo della ricerca.

In the article we determine the suitability of the phytocenose as a basic unit for determining soil susceptibility to mechanized logging. A total of 90 measurements of skid trail profiles were taken on a 13.9 km long sample transect. The forest infrastructure studied was categorized into primary and secondary skid trails, trails intended for CTL harvesting and undocumented trails. The following indicators were determined on the profiles: tyre track depth, trail width, trail slope, amount of rock present, presence of roots and road category. The deepest ruts were found in Blechno-Fagetum (6.9 cm), followed by Galio rotundifolii-Abietetum (6.4 cm) and Hacquetio-Fagetum (5.6 cm), while the shallowest ruts were found in Omphalodo-Fagetum (5.3 cm). The deepest ruts were found on primary skid trails (7.0 cm), followed by secondary skid trails (5.8 cm), while the shallowest ruts were found on skid trails used by CTL technology and on undocumented trails (1.9 cm). No significant difference in track depth was found between the four individual phytosociological units, but more extensive research should be conducted in the future.

Questo articolo ha per progetto il settore forestale produttivo della Nuova Zelanda e, a differenza della maggior parte dei contributi di "Oltre Confine", non riporta un progetto o uno studio realizzato all'estero per poterne evidenziare possibili ricadute o replicabilità in Italia, ma descrive invece una realtà forestale assai diversa da quella italiana e anche per questo molto interessante. Attraverso le testimonianze dei due Autori, che così bene conoscono le realtà produttive italiane e neozelandesi, sarà interessante fare delle riflessioni e magari prendere qualche spunto utile dall'approccio gestionale del settore forestale neozelandese.

La Nuova Zelanda è un paese posto all'estrema periferia del mondo, in una condizione particolare isolamento. Ha una popolazione di 5 milioni di abitanti, non ancora sufficiente a sfruttare pienamente le abbondanti risorse naturali offerte dalle sue due isole principali. Il grosso dell'economia neozelandese dipende dall'esportazione di materie prime o di prodotti semilavorati, in particolare di carne, latte e legname. Proprio la produzione di legname rappresenta un settore economico di grande rilevanza per la Nuova Zelanda ed è sostenuta a tutti i livelli. Le scelte selvicolturali neozelandesi mostrano un notevole successo delle piantagioni industriali. In queste, al momento del taglio, si hanno dei cantieri dotati di un elevato grado di meccanizzazione. Il contributo riporta le testimonianze degli Autori sotto il punto di vista della produttività e della sicurezza nei cantieri. Gli stessi autori affrontano altri aspetti della realtà neozelandesi nella sezione "Oltre Confine" presente nel numero 238 di Sherwood dove si cercano di evidenziare le differenze tra settori forestali di Italia e Nuova Zelanda.

Winching is common in small-scale forest operations, especially on steep slopes, where tractors cannot reach the logs inside the forest. In this case, logs are dragged to the roadside with tractor-mounted winches, for later collection by transportation units. Winching is a heavy task, posing a high physiological stress on winching crew members. The aim of this study was to investigate the relationship between experienced workload, work conditions and operator fitness. The study confirmed the assumption that fit, young operators experience a lower workload than older ones. Workload depends on winching direction, and it is higher when winching downhill than when winching uphill. Results confirmed that gravity is the main factor, and it has a stronger effect than task type and tool weight. Walking uphill with no tools is heavier than walking downhill and carrying a steel cable. As a consequence, tool weight reduction can only palliate the problem, without solving it. Winching crews should be composed of fit, young workers. When the task is assigned to older workers, it is necessary to allow longer rest breaks, accepting a lower productivity.

Nell'ambito del Progetto Integrato di Filiera "Dall'Appennino al mare: energia toscana al 100%", cofinanziato dal PSR 2014-2020 della Regione Toscana, relativo alla sottomisura 16.2 "Cippato & Cippatino", il CNR-IVaLSA (Consiglio Nazionale delle Ricerche - Istituto per la Valorizzazione del Legno e delle Specie Arboree), coadiuvato dagli altri partner del Progetto, ha condotto un'indagine per conoscere l'attuale realtà italiana delle aziende che producono pellet di legno o microcippato, altrimenti chiamato cippatino.

Come già avvenuto per le fustaie italiane, negli ultimi anni stiamo assistendo all'ingresso della meccanizzazione avanzata anche all'interno delle utilizzazioni del ceduo. Molte imprese hanno iniziato a sostituire la motosega con teste abbattitrici a disco o con cesoie applicate ad escavatori cingolati. Dove è possibile accedere in bosco con questi mezzi è stato riscontrato un sensibile miglioramento della sicurezza ; l 'operatore, infatti, è protetto all'interno della cabina dell'escavatore da eventuali impatti e schiacciamenti causati dagli alberi abbattuti. Inoltre l 'abbattimento meccanizzato delle ceppaie riduce i costi di utilizzazione , ciò si riflette sul prezzo del prodotto finito rendendo/o concorrenziale con quello proveniente dall'estero.

A survey of cable logging contracts was conducted in 5 of the 8 Alpine countries, namely: France, Germany, Italy, Slovenia and Switzerland. The goals of the survey were to set a general reference for cable logging rates, to identify eventual differences between countries and to determine the effect of technical work parameters (i.e. piece size, removal per hectare, line length) on actual contract rates. With a total sample size of 566 units, the mean removal and rate were 165 m3 ha-1 and 42.9 EUR m-3, respectively. Both removal per hectare and contract logging rates varied considerably and the study found significant differences between countries. Switzerland stood out from the group with the highest removal (345 m3 ha-1), but also the highest contract rate (79.5 EUR m-3). Removal per hectare was lowest in Italy with just 58.3 m3 ha-1, and logging rate lowest in Slovenia at 29.3 EUR m-3. Logging rates were highly correlated with the average labour rate of each country. Technical factors such as tree size, line length and tract size explained about 40% of the variability in logging rates. Therefore, 60% of the variability is explained by other technical factors not included in our data and by non-technical factors, such as local market dynamics.

Integrated biomass harvesting system is one of the conventional biomass utilisation methods applied in Australian pine plantations. This project studied the productivity-cost and yield of this harvesting system in 32 years old Pinus radiata plantations located in South West Western Australia. The harvesting systems consisted of a harvester and a forwarder. There were two study treatments; control plot (extracting saw log and chip wood) and fibre-plus plot (integrated sawlog, chip wood and fibre-plus (residue logs as source of biomass)). In the integrated biomass harvesting plot, 36.6 GMt/ha of Fibre-plus materials were utilised in addition to the normal sawlog and chip wood volumes. Extracting additional biomass materials reduced the productivity of the forwarder and increased the cost of extraction (2.7 $/GMt) compared to the control plot (2.2 $/GMt) but the harvester's productivity and cost did not change highly in both plots. DBH was significant factor influencing the working time of harvester while load volume, extraction distance and extraction type (sawlog, chip wood, chip wood and Fibre-plus) significantly impacted forwarding time. Additional biomass recovery in the Fibre-plus plot resulted in less residues left on the site (103.2 GMt/ha) than control plot (144.2 GMt/ha).

I gas di scarico generati dalla combustione del gasolio contengono composti chimici in forma gassosa e solida (particolato) le cui dimensioni sono abbastanza piccole da raggiungere il sistema respiratorio e il cervello provocando nell'immediato nausea, tosse ed emicrania, mentre nel lungo periodo effetti negativi sul sistema cardiovascolare e respiratorio.

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.

The study explores the possibilities of recovering sawlogs from pulp-size poplar plantations. Under recent short-rotation high-density management practice, only 1.2 percent of the trees reach the minimum size and form requirements for timber production. Separating the sawlogs from the primary pulp chip harvest is technically feasible and requires four additional tasks: selection and marking, separation while forwarding, merchandising, and loading. It also allows saving the cost of delimbing-debarking-chipping. At present, separation costs $42 per green ton, which makes separation profitable. What's more, there is a potential for halving this figure if the harvesting system is improved according to the findings of the study. The most expensive task is marking and selection, which is performed manually; at present this work accounts for 72 percent of the separation cost. Furthermore, a more flexible merchandising strategy may be needed. Limiting sawlog production to one fixed length means making poor use of the potential yield of the trees; since separation cost decreases with sawlog yield, increasing sawlog recovery provides a substantial economic benefit. Despite its marginal character, the recovery of sawlogs from pulpwood plantations can become economically viable and help differentiate production so as to exploit a wider range of market opportunities. In this context, optimizing the harvesting system is crucial to reaching the appropriate cost and quality goals.

Uno studio del CNR IVaLSA ha permesso di dimostrare come l'utilizzo de "Il Piccino" durante le operazioni di esbosco permetta un risparmio effettivo di tempo, costi e fatica.

The authors tested the same modern mid-size tower yarder for uphill and downhill extraction. The yarding machine is a popular commercial model offering state-of-the-art yarding technology, including telescoping tower and full hydrostatic transmission. The machine was studied while harvesting selective patch cuts (gap cutting) in similar even-aged Norway Spruce stands, extracting logs between 3 and 6 metres long. The operation was carried out by the same experienced 3-man crew. Productivity ranged between 8.5 and 10 m3/h, including all delays, but excluding set-up and dismantle time. A set of regression equations for estimating machine productivity were calculated as a function of the main work conditions, such as yarding distance, lateral extraction distance, mean log size and number of logs per turn. Machine utilization was about 60%, which is consistent with previous studies. In general, cable logging is more complex and expensive than ground-based logging, which places steep terrain forestry at a general disadvantage in terms of pure harvesting cost. However, modern cable yarding technology can reduce this gap, and productivity models can assist users in refining their work technique, so as to maximize the productive potential of their machines.

Chipping is an essential element in the energy supply chain and mobile chippers are very popular because they can work directly in the forest or at the roadside landing. Due to space constrain, drum chippers are dominating forest biomass operations. Drum chipper are less efficient then disc chipper but they are also less sensitive to feedstock quality. Drum chippers come in two main design types: closed drum with full-length knives and open drum with staggered narrow knives. The goal of this study was to analyse the specific effect of these design types on productivity, fuel consumption and product quality, using different raw material types. For this purpose, two commercial chipper models with almost identical characteristic were selected to represent the alternative drum designs. Both machines were fed with two different feedstock types: chestnut logs and chestnut branches. The study included 12 repetitions per combination of drum design, feedstock type and knife condition (new or worn out) for a total of 2 x 2 x 2 x 12 = 96 repetitions. Both chippers were attached to the same instrumented tractor, and all product obtained from each chipping bout was blown into big bags and weighed with a load cell attached to a forklift. The study showed that the closed drum design was better suited to handle branch material, compared to the open drum design, especially when knives were dull. Under these conditions, productivity was higher, fuel consumption lower and chip quality better for the closed drum design. No significant differences between the two designs were found when processing logs or when the knives were new. In general, the performance of both designs was significantly affected by feedstock type and knife wear.

The authors conducted a comparative study of continuous timing and work sampling, as applied by different observers. Twelve researchers were split into two groups and carried out the same study, switching method every half an hour. The study lasted 3 hours, corresponding to 6 iterations (3 iterations per method). Statistical analysis of data confirmed that both methods may determine elemental breakdown with the same accuracy. Observer-induced variability had a minor effect, and only on those time elements that were short and occurred less frequently. Error increased as the study progressed, as the likely result of observer fatigue. Again, this trend was significant for short elements and not significant for longer ones. This study may offer a warning against over-detailing elemental breakdown. Work cycles should be split in as many elements as strictly necessary for achieving the specific purpose of the study. Splitting them in too many elements just for the sake of description is counterproductive, because it places an excessive strain on the observer and it may increase the risk of errors. A simple study design will facilitate replication by a number of different researchers, regardless of method.

In this study we examined the effect of specific factors on chipper performance by using a mobile industrial chipper in a real-life commercial setting. The comprehensive experimental design consisted of five replications per each combination of two types of raw material, two chip discharge systems, and two cut lengths (i.e., 5 × 2 × 2 × 2 = 40 replications). Each replication consisted of a full 18-m3 trailer load. Cut length was manipulated by using different drum types. When all else was equal, the doubling of cut length resulted in a 50 percent increase of average chip length, a 15 percent increase of net productivity, and a 15 percent decrease in fuel consumption. The handling characteristics of the raw material had a strong impact on chipper productivity', causing variations on the order of 20 percent. The discharge system had no significant effect on fuel consumption or productivity, but it did impact product quality and bulk density. Using a blower allowed increasing bulk density between 4 and 7 percent, whereas the installation of a belt conveyor reduced the incidence of small chips and fine particles by up to 30 percent.

Approximately half of the Italian forest area is classified as coppice forest, mostly managed for the production of firewood. Chestnut (Castanea sativaMill.) coppice stands make exception, as they also produce more valuable assortments, such as sawlogs, poles and fencing materials. Hence the significantly higher industrial activity in chestnut coppice stands, and the rapid introduction of mechanized harvesting. This study deals with four different harvester units used for processing (delimbing - bucking) chestnut trees fromcoppice stands, at the landing. For these four different machines, time studies were conducted in order to estimate productivity and compare the performance. The results show that the processors can reach high productivities (7.7m3/PMH0-19.8m3/PMH0). In one study the influence of tree form has been estimated, proving that the size of the branches and the shape of the stem have a significant effect on machine productivity. The difference can reach 2.3 m3/PMH0 for stems with a volume of 0.2 m3.

I risultati delle prove condotte dal Cnr Ivalsa sull'orizzontale Caravaggi Bio 900

In central Italy, the increasing demand for fuel chips and the epidemic spread of maritime pine bast scale have favored the development of large-scale industrial logging operations. After years of extensive commercial trials, local operators have developed their own industrial harvesting systems, through a wise mix of Scandinavian and North American methods. The result is original and effective, and allows keeping harvesting cost below 20 EUR gt -1. The study compared terrain chipping with roadside chipping, as applied to the coastal pine stands of Tuscany. Under the conditions of our study, roadside chipping was over four times more productive than terrain chipping, and it allowed reducing harvesting cost by one third (12.3 vs. 18.3 EUR gt -1). Despite the intense use of diesel, total fossil energy inputs accounted for less than 3% of the potential energy in the wood chips. Terrain chipping and roadside chipping yielded 36 and 47 times the energy they used, respectively. The coexistence of the two systems was most interesting. The harvesting systems described in the study perform best in clear-cuts, but they can also work in partial cuts, including thinning operations. They are actually used in thinnings in the same Regional Park of San Rossore, although their productivity is lower than in clear-cuts.

L'allestimento meccanico del pioppeto è accusato ingiustamente di causare perdite in valore; in realtà le prove hanno dimostrato come i sistemi manuale e meccanico diano risultati simili, la differenza sta nella professionalità degli operatori.

The authors tested two alternative treatments for small wood extraction in protected conservation areas, respectively based on direct skidding by small crawler tractors and integrated horse bunching and crawler tractor skidding. The integration of horse bunching with tractor skidding proved cheaper than direct tractor skidding, and allowed extending the distance range of horse skidding. Integration also offers many additional benefits, as it can improve work safety and system sustainability. The performance of the integrated system can be optimized by paying special attention to team balance and by manipulating extraction distance. In industrialized countries, the number of horse loggers is so small that they may not contribute large wood volumes to the markets: however, the integration of animal and mechanical power may allow making the most efficient use of the few remaining horse logging operations, and increase their contribution to low-impact, cost-effective wood extraction in protected conservation areas. A similar and converse effect could be obtained in developing countries, where integration would allow making the most efficient use of the few available tractors. Efficient use of draught horses may also help increasing horse logger revenues, thus providing a further motivation to stay in business, and contributing to environmentally compatible economic development.

Short rotation coppice (SRC) is one of the most promising sources of woody biomass for energy in the frame of the European renewable energy strategy. While the study of improved clones and growing techniques is extremely important for future developments, the availability of reliable and cost effective harvesting systems is crucial for the very existence and sustainability of any SRC program. In fact, harvest and logistics of biomass can constitute up to 70% of the overall production costs of SRC biomass production. At present, commercial harvest operations in Italy are accomplished with modified foragers equipped with dedicated SRC headers. The present study provides an overview of the main characteristics and performance of four different models of forager/SCR header deployed in Italy., Proceedings of the 19th European Biomass Conference and Exhibition, 6-10 June 2011, Berlin, Germany, pp. 678-679

The pressures of global competition on wood harvesting have resulted in a massive trend toward mechanization. However, for use in mountain forests, the classic system for harvesting, transporting, and processing trees must be modified. Harvesters and forwarders to process and transport trees on steep terrain have been built, but none has really been successful.

Industrial poplar plantations represent a strategic source of wood products for many countries. Harvested after 10 to 30 years, they yield about 200 t ha-1 of timber and 100 t ha-1 industrial wood. The latter is obtained from poplar tops, which can be converted into chips, or a mix of pulpwood and chips. The study compared four options to process poplar tops. Alternatives derived from the intersection of two product strategies (pulpwood and chips, or chips only) with two pulpwood processing methods (manual or mechanized). Both mechanization and simplification (only one product) succeeded in reducing production cost, but the former had a stronger effect. The tests demonstrated that all options were cost-effective and could return some profits. However, the exclusive production of chips offered lower profits, compared to an articulate product strategy aimed at maximising value recovery. In the case of Italian poplar plantations, the price difference between pulp and chips is generally larger than the cost reduction obtained with integral chipping. Similar conclusions were reached by other authors working with spruce and beech in Central Europe. Of course, this is only true for the current price levels of pulpwood and chips: results may change, if this price balance will be altered by the growing demand for biomass fuel.

The recovery of agricultural woody residues for energy production is arising a growing interest in European Countries. Many aspects must be better understood in order to fully control the factors defining the technical and economic viability of field-to-boiler biomass procurement projects. A comprehensive overview of the available equipment and its main characteristics may be useful for the definition of the best solutions to be implemented according to the vineyard characteristics, the professional level required (ranging from farm level self­production to contractors), and the type of final user (farm size boiler to district heating plants). Italian manufacturers propose to the local market a wide choice of machinery (over 60 models) dedicated to the harvest and transformation of agricultural residues, with a specific attention to vineyard residues. These machines can be roughly divided in two main groups, balers and comminuters. Balers can be both purpose designed machines (smaller and agile) or the lighter models of common agricultural balers. Comminuters are generally mulchers equipped with a bin or an expulsion system for loading the biomass onto a trailer. The present work reports a brief description of the results of the studies conducted by CNR-IVALSA on vineyard residues harvesters., Proceedings of the 19th European Biomass Conference and Exhibition, 6-10 June 2011, Berlin, Germany, pp. 542-543

The Authors set out to determine the particle-size distribution, the fiber and bark content, and the heating value of a wide sample of wood chips, collected from 60 commercial biomass terminals active in Northern Italy. This sample was meant to represent a cross-section of the Italian fuel chip market, and focused on four main feedstock types: sawmill residues, logging residues, small trees and short rotation coppice (SRC). Overall, the Authors collected 300 samples, each weighing approximately 1 kg. Particle-size distribution was determined with an automatic screening device on 210 samples, according to European Standard CEN/TS 15149-1. All samples were also manually separated into the following main components: fiber, bark, twigs, leaves, dust and other. The higher heating value (HHV) was determined on 56 one-gram subsamples using an adiabatic bomb calorimeter. Sawmill residues and small trees offered the best quality, with high fiber content (85-90%) and favorable particle-size distribution. On the contrary, both logging residues and SRC presented a high bark content (>= 20%) and occasionally a mediocre particle-size distribution, being often too rich in fines (>= 10%). These problems were especially serious with fuel derived from 1-year old SRC sprouts. There is a need for reducing the supply cost of small trees, and improving the quality of SRC biomass.