CNR Tree and Timber Institute

San Michele all'Adige, Italy

CNR Tree and Timber Institute

San Michele all'Adige, Italy
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Spinelli R.,CNR Tree and Timber Institute
Forest Policy and Economics | Year: 2010

The growing interest in forest biomass has made chipping increasingly popular all across Europe. Many operators have equipped for the purpose, but the large variety of working conditions found in the European forests makes it difficult to correctly estimate the productivity of each specific operation, leading to uncertainty in crucial decisions, such as: operation scheduling, price setting, machinery selection and acquisition. In 2001, the Italian National Council for Research (CNR) and the University of California (UC) developed a spreadsheet freeware capable of returning reliable estimates of chipping productivity and cost, on the basis of user-defined input data. The model is still available from the CNR website and is the object of frequent downloading and inquiries. Such model contains a set of predictive equations derived from the results of 102 field trials, conducted with 30 different machines, under a range of working conditions. In order to facilitate comparison with other estimates and to achieve methodological transparency, the equations are assembled into a simple Microsoft Excel workbook, and the costs are calculated with standard costing methods currently used in Forest and Agricultural Engineering. Since then CNR has continued to work on the subject, with the goal of updating and refining the model. Such work has included 45 validation tests and a separate study on the delay (idle) time typical for different chipping operation layouts. The study was concluded in 2009 and confirms that the model developed by CNR can provide reliable estimates of chipper productivity under a range of operational conditions. Authors believe that such a model can assist European foresters in keeping ahead with the growing biomass sector, thus helping them to seize an important business opportunity. © 2009 Elsevier B.V. All rights reserved.

Manzone M.,University of Turin | Spinelli R.,CNR Tree and Timber Institute
Biomass and Bioenergy | Year: 2013

The authors tested a 409kW forager turned into an industrial chipper through a special conversion kit. Conversion was temporary, and the forager could be returned to its original occupation with one day of work. The converted forager proved as effective as a dedicated chipper of the same power. Net chipping productivity varied between 25 and 33greenth-1. Productivity was highest with poplar tops and lowest with pine tops. Fuel consumption ranged from 1.6 to 1.8lgreent-1. Fuel consumption did not change with tree species, but increased significantly with knife wear. Temporary conversion allowed a better depreciation of the invested capital and resulted in a 25% reduction of unit chipping cost. The converted forager proved an ideal solution wherever the production of wood chips was a complementary business within the scope of a larger agricultural economy. In technical terms, this machine offered the combined advantages of road-capability and good off-road mobility, allowing low-cost independent relocation and effective in-field chipping. © 2013 Elsevier Ltd.

Benelli C.,CNR Tree and Timber Institute | De Carlo A.,CNR Tree and Timber Institute | Engelmann F.,IRD Montpellier
Biotechnology Advances | Year: 2013

This paper presents the advances made over the last decade in cryopreservation of economically important vegetatively propagated fruit trees. Cryopreservation protocols have been established using both dormant buds sampled on field-grown plants and shoot tips sampled on in vitro plantlets. In the case of dormant buds, scions are partially dehydrated by storage at - 5 °C, and then cooled slowly to - 30 °C using low cooling rates (c.a. 1 °C/h) before immersion in liquid nitrogen. After slow rewarming and rehydration of samples, regrowth takes place either through grafting of buds on rootstocks or excision of apices and inoculation in vitro. In the case of shoot tips of in vitro plantlets, the cryopreservation techniques employed are the following: controlled rate cooling procedures involving slow prefreezing followed by immersion in liquid nitrogen or vitrification-based procedures including encapsulation-dehydration, vitrification, encapsulation-vitrification and droplet-vitrification. The current status of cryopreservation for a series of fruit tree species including Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis is presented. Routine application of cryopreservation for long-term germplasm storage in genebanks is currently limited to apple and pear, for which large cryopreserved collections have been established at NCGRP, Fort Collins (USA), using dormant buds and in vitro shoot tips, respectively. However, there are a growing number of examples of pilot scale testing experiments under way for different species in various countries. Progress in the further development and application of cryopreservation techniques will be made through a better understanding of the mechanisms involved in the induction of tolerance to dehydration and cryopreservation in frozen explants. © 2012 Elsevier Inc.

Santoni I.,CNR Tree and Timber Institute | Pizzo B.,CNR Tree and Timber Institute
International Journal of Adhesion and Adhesives | Year: 2011

Wettability of 6 different wood species commonly used in the woodworking industry in the Mediterranean region was evaluated in this study. The species were Norway spruce (Picea abies Karst.), umbrella pine (Pinus pinea L.), oak (Quercus sp.p.), chestnut (Castanea sativa Mill.) beech (Fagus sylvatica L.) and poplar (Populus sp.p.), and their surfaces were machined according to 3 different processes: planing, sanding and disc-sawing. Measurement of dynamic contact angle and extractives (evaluated by means of GCMS analysis) were carried out on freshly cut and 24 h air exposed surfaces, in order to also evaluate the effect of ageing on wettability. The parameterisation of the contact angle vs. time curves allowed for the systematic statistical elaboration of data, in order to find the relationships existing between the four parameters characterising the dynamic curves and the considered factors (species, machining, ageing). The evaluations evidenced a different influence of these factors on the chosen parameters and hence some of them could be used to reliably assess both wood wettability and the effects of the factors here considered. In general softwoods showed higher contact angles than hardwoods due to the different anatomy and to the presence of resins and terpenes in addition to fatty acids and phenolic compounds, also present in hardwoods. After 24 h air exposure a shifting upwards of dynamic contact angle curves was observed but, despite the variation in surface composition, this shifting was imputable to other inactivation factors. Also machining appreciably influenced wettability, and the sanded surfaces were the most wettable as compared to both the planed and the disc-sawn ones. On the other hand, these observed differences diminished after ageing due to the levelling effect of inactivation that overcame surface inhomogeneities. © 2011 Elsevier Ltd. All rights reserved.

Spinelli R.,CNR Tree and Timber Institute | Magagnotti N.,CNR Tree and Timber Institute
Small-scale Forestry | Year: 2012

A winch and a sulky can transform a farm tractor into an effective small-scale logging machine, closely resembling a wheeled cable skidder. The additional cost of these implements is very small, but they offer significant benefits when extracting timber under the conditions of small-scale forestry. The authors developed a productivity model for skidding timber with wheeled farm tractors, equipped with winch and sulky. The origin data pool contained over 300 individual skidding cycles, extracted from 8 separate tests. Statistical analysis of the data allowed calculating a simple mathematical relationship for estimating skidding productivity as a function of significant work conditions, such as: piece size, winching distance, tractor power, skidding distance and crew size. This model can provide useful directions to prospective users, contributing to operation planning, costing and optimization. It can predict a large proportion of the variability in the data and was successfully validated using reserved cycle records, extracted from the same data pool and not used for model development. Depending on tractor power and piece size, the average turn volume and productivity can exceed respectively 2 m 3 per cycle and 4 m 3 per Scheduled Machine Hour (SMH). Top performance can reach 8 m 3 SMH -1, with heavy tractors and large logs. © 2011 Steve Harrison, John Herbohn.

Nati C.,CNR Tree and Timber Institute | Spinelli R.,CNR Tree and Timber Institute | Fabbri P.,CNR Tree and Timber Institute
Biomass and Bioenergy | Year: 2010

The study investigated the effect of wearing chipper knives on machine productivity, fuel consumption and particles size distribution. The test included two different tree species (poplar and pine), two tree parts (branches and logs) and two screen types (large and medium). Chip quality was defined by CEN international technical standards. Knife wear causes a significant reduction of chipping productivity and a remarkable increase of fuel consumption. The replacement of the standard wide mesh screen with a narrower screen has a similar effect, further decreasing productivity and increasing fuel consumption. For the same screen type and knife wear level, productivity and fuel consumption are the same for poplar and pine. Knife, tree species and tree part also have a significant impact on chip size distribution. Chips produced from logs always contain a smaller proportion of oversize particles and a higher proportion of accepts. For the same large mesh screen, poplar chips tend to be larger than pine chips and to contain a higher proportion of oversize particles. On the contrary, pine chips tend to be smaller and to contain a higher proportion of fines. The use of a narrower mesh screen on pine material does not seem to offer any significant reduction of oversize particles, whose presence is already very limited. Therefore, a standard large mesh screen should be used when chipping pine material. © 2010 Elsevier Ltd. All rights reserved.

Magagnotti N.,CNR Tree and Timber Institute | Spinelli R.,CNR Tree and Timber Institute
Ecological Engineering | Year: 2011

The authors compared the financial and energy performance of horse and tractor skidding, under the conditions of continuous cover forestry (CCF) operations in steep terrain. Horse skidding incurs lower unit costs than tractor skidding, when the extraction distance is short or when pre-existing skidding trails are not available. The cost-efficiency of horse skidding is significantly increased by detaching two horses per driver, since the additional cost of the second horse is lower than the additional productivity it generates. Furthermore, it is more difficult to find drivers than horses, and using two horses per driver is a good way to extend the capacity of the few remaining horse-logging operations. Horse logging requires from 8 to 20 times less fossil energy inputs than tractor extraction, and a significant share of its fossil energy use (10-50%) is caused by relocation on motor vehicles. When necessary, trail building adds 30-60% to the unit consumption of fossil energy in the tractor system. In general, the forestry system considered in this study requires from 12 to 60 times less fossil energy than conventional agricultural systems, and it contributes very little to the dependence on non-renewable energy sources. © 2011 Elsevier B.V.

Spinelli R.,CNR Tree and Timber Institute | Magagnotti N.,CNR Tree and Timber Institute
Scandinavian Journal of Forest Research | Year: 2010

This study compares two principally different harvesting systems used for the thinning of Norway spruce [Picea abies (L.) Karst.] plantations in the Alps. The first system was whole-tree harvesting (WTH), producing only whole-tree chips for energy purposes. This system minimizes the production costs by simplifying the harvesting process. The other system was cut-to-length (CTL) mechanical harvesting with an excavator-based harvester. This system maximizes value recovery by producing both short sawlogs and quality fuel chips. Trials were conducted on two similar sites in the Dolomites, in northern Italy, and demonstrated that the CTL system resulted in slightly higher harvesting costs, and also higher revenue. The price differences between the different products determine which system offers the best economic results. If the delivered price of sawlogs does not exceed €25 t-1, WTH and CTL harvesting offer very similar economic performances, and become profitable only if the delivered price of raw chip wood exceeds €40t-1. If the delivered price of sawlogs increases to €50t-1, the mechanized CTL system always becomes preferable, and it will turn some profits when the price of raw biomass exceeds €35t-1. The CTL system is less sensitive to long extraction and transport distances than the WTH system. © 2010 Taylor & Francis.

Magagnotti N.,CNR Tree and Timber Institute | Pari L.,Italian Agricultural Research Council | Spinelli R.,CNR Tree and Timber Institute
Ecological Engineering | Year: 2012

In an attempt to perpetuate traditional forest management, the authors tested a new compact tractor designed to replace pack mules when harvesting firewood from Mediterranean coppice stands. The new machine was capable of replacing a standard eight-mule team, and small enough to use the same infrastructure. The main characteristics of the tractor were its narrow width, a shifting center of gravity and a capacity to unitize loads for more efficient handling. The tests showed that the new tractor can outperform an equivalent mule team under the same working conditions, doing the job without incurring a higher cost. Installing a remote control can enhance operator safety, and bring it to the same good levels achieved with animal extraction. Even if the new machine can fill the technical role of pack mules, it certainly cannot reflect the same cultural and historical value. This research was never spurred by the desire to replace draught animals, but rather by their rapidly declining numbers, and was undertaken with the purpose of preserving traditional coppice management. There is a cultural and ethical obligation to preserve animal logging, which can partly be obtained through optimized deployment, so as to increase animal logger revenues and provide them with a further motivation to stay in business. © 2011 Elsevier B.V.

Spinelli R.,CNR Tree and Timber Institute | Picchi G.,CNR Tree and Timber Institute
Bioresource Technology | Year: 2010

In Mediterranean countries, olive tree pruning residue represents an abundant source of energy biomass, still largely unexploited for lack of cost-effective harvesting technology. The authors tested two industrial pruning harvesters, capable of overcoming the limits of lighter units appeared in the past years. One of the machines was designed for application to a powerful farm tractor, whereas the other was a self-propelled dedicated harvester. Data were collected from 10 operations, covering a total of 69 hectares and producing over 190 tonnes of wood fuel. Recorded productivity varied between 3 and 9 tonnes per scheduled machine hour (SMH), or 2-7 oven dry tonnes (odt) SMH-1. Harvesting cost varied from 17 to 52 € t-1, with an average value of 28 € t-1: these values correspond, respectively to 22, 70 and 40 € odt-1. This compares very favourably with the average 1-1.5 ton SMH-1 offered by lighter commercial units. Productivity was related to residue density, row length and forwarding distance. Mechanical availability was high and over 90%, for both machines. The authors also developed a simple deterministic model capable of predicting harvesting productivity and cost, as a function of significant site and economic conditions. The model can also be used to determine the break-even utilization level, below which the operational flexibility of a tractor-mounted operation becomes preferable to the higher productivity of a specialised unit. © 2009 Elsevier Ltd. All rights reserved.

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