816 research outputs found
Harvesting systems for steep terrain in the Italian Alps: state of the art and future prospects
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 system, even if innovative ground-based harvesting systems have been proposed in the last years. In this context, the present works aim 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 networ
How Wood Fuels\u2019 Quality Relates to the Standards: A Class-Modelling Approach
The quality requirements of wood biofuels are regulated by a series of harmonized international standards. These standards define the technical parameter limits that influence the quality of solid biomass as a fuel. In 2014 the European reference standard for solid biofuel was replaced by the International ISO standard. In the case of wood chips, the main difference between the European and International standards is the definition of particle size distribution classes. In this context, this study analyses the quality of wood chips and its variation over the years according to the \u201cformer\u201d (EN 14691-4) and \u201cin force\u201d (ISO 17225-4) standards. A Soft Independent Modelling of Class Analogy (SIMCA) model was built to predict the best quality of wood chips and to clarify the relationship between quality and standard parameters, time and changes in the standard regulations. The results show that, compared to the EN standards, classification with the ISO standards increases the samples belonging to the best quality classes and decreases the not classified samples. Furthermore, all the SIMCA models have a high sensitivity (>90%), reflect the differences introduced to the quality standards and are therefore suitable for monitoring the quality of wood chips and their changes
Determination of forest road surface roughness by kinect depth imaging
Roughness is a dynamic property of the gravel road surface that affects safety, ride comfort as well as vehicle tyre life and maintenance costs. A rapid survey of gravel road condition is fundamental for an effective maintenance planning and definition of the intervention priorities. Different non-contact techniques such as laser scanning, ultrasonic sensors and photogrammetry have recently been proposed to reconstruct three-dimensional topography of road surface and allow extraction of roughness metrics. The application of Microsoft Kinect\u2122 depth camera is proposed and discussed here for collection of 3D data sets from gravel roads, to be implemented in order to allow quantification of surface roughness. The objectives are to: i) verify the applicability of the Kinect sensor for characterization of different forest roads, ii) identify the appropriateness and potential of different roughness parameters and iii) analyse the correlation with vibrations recoded by 3-axis accelerometers installed on different vehicles. The test took advantage of the implementation of the Kinect depth camera for surface roughness determination of 4 different forest gravel roads and one well-maintained asphalt road as reference. Different vehicles (mountain bike, off-road motorcycle, ATV vehicle, 4WD car and compact crossover) were included in the experiment in order to verify the vibration intensity when travelling on different road surface conditions. Correlations between the extracted roughness parameters and vibration levels of the tested vehicles were then verified. Coefficients of determination of between 0.76 and 0.97 were detected between average surface roughness and standard deviation of relative accelerations, with higher values in the case of lighter vehicles
GIS applications in forest operations and road network planning: An overview over the last two decades
A systematic literature review was settled to investigate the application of GIS in terms of
methods, complexity and accuracy to support decision on forestry operations and forest road
network planning. A comprehensive search for relevant studies was performed to retrieve as
many relevant international scientific publications dealing with forestry operations and forest
road network planning in the period 1996\u20132015.
The analysis was based on the development of a systematic literature review comprising three
steps:
\uf0de implementation of the database searches by well-defined search terms
\uf0de identification of all the publications meeting the requirements of the search terms by abstract
\uf0de choice of the most relevant publications analysis of the contents.
In this review, \ubbGIS and forest operations\uab includes all the descriptors dealing with GIS ap-
plied to support forest operations decision and analysis, while \ubbGIS and forest roads\uab includes
all the papers dealing with the analysis, management and planning of forest road or forest road
networks. A total of 372 references and 82 publications were selected for the analysis as they
were clearly in conformity with the review topics (GIS applications in forest operations and
road network planning).
The analysis showed that GIS has also been applied successfully and unambiguously to har-
vesting and transportation engineering in forest operations management. Further to the pre-
vailing use concerning applications to support tactical planning, a significant number of recent
publications have turned successfully to GIS applied at operational level. Again, despite the
prevailing use concerning applications to support tactical planning, a significant number of
recent publications have also turned successfully to GIS applied at operational level with the
topics of Forest Operations Management in terms of optimization, productivity and safety
analysis.
By considering the recent evolution and improvement of GIS technology and the increasing
availability of spatial data, as well their improvement in quality and resolution, the application
of GIS in forest harvesting and transportation engineering as well as in forest operations
management will expand in the near future
Spatial multi-criteria decision process to define maintenance priorities of forest road network: an application in the Italian Alpine region
The combination of GIS tools and Analytic Hierarchy Process (AHP) techniques is used to develop a Decision Support System to rank the maintenance priorities of a forest road network according to the actual conditions and needs. The decision-making process is divided into 4 stages. The first stage fixes the objectives of the analysis as the minimization of the sediment production from road surface and the maximization of the social value of the road. The second
stage defines the hierarchical structure of the decision problem. At this stage the set of factors (criteria) to maximize each objective and the evaluation methods are defined. At the third stage AHP analysis is applied using a specific application running on ArcGIS, to calculate the evaluation layer that represents the importance of each road according to the set objectives. The values of the evaluation layer are used at the fourth stage to rank the maintenance interventions according to the given benefit. The methodology has been tested in a forest road
network with an extension of 107.8 km including in the analysis the real budget constraints and maintenance costs.
The results show that the integrated use of GIS and AHP analysis represents a valuable tool to rate the importance of the forest road network for the management of a mountain territory and to define priorities among maintenance operations of the road network, in order to maximize the overall benefit with limited economic resource
DETERMINATION OF THE FOREST ROAD NETWORK INFLUENCE ON THE SUPPLY CHAIN FOR FIREWOOD PRODUCTION BY DISCRETE EVENT SIMULATION
In this study a Discrete-event simulation (D-es) has been developed to analyze the wood supply chain for firewood production in a mountain area in North-eastern Italy. The D-es is applied in the modeling of extraction (Full Tree System), processing of roundwood into wood assortments (cross-cut and sorting), offroad and on-road transport. In order to estimate the productivity functions and parameters, field studies were conducted to gather data about the different operations linked in the model. Also a GIS network analysis was developed to integrate the spatial information onthe covered distance to the D-es model for each of the supposed Scenarios. The results indicats that an increment of 5 m ha-1 of the forest road network could significantly increase the productivity of the wood supply chain up to 2%
Productivity and quality performance of an innovative firewood processor
The growing interest about wood as fuel regards not only wood chips and pellets but also firewood, especially in mountain and rural areas where domestic heating plants are widely used. Due to the increased demand for firewood, harvesting activities have extended on broadleaved high forests as well as coppice. As a consequence, the diameter of logs has increased requiring larger and larger splitting machines; nowadays it is not uncommon to find on the market splitters able to process logs with diameter up to 50-60 cm. In order to increase the productivity, the effort of machine producers is directed to obtain the complete splitting of the log into firewood in only one step using multiple ways splitting knives. This technical solution may cause some drawbacks especially when the splitting knives are not properly adapted to the log diameter; it happens that the size of firewood is not homogeneous and splinters are produced, which requires using screens to separate them from the main product. In order to evaluate the work quality of a firewood processor, equipped with multiple ways splitting knives, an experimental test has been carried out using a machine in which the log diameter is automatically detected through a laser device; according to the log diameter the multiple ways splitting knives (formed by fixed and mobile knives, the latter hydraulically operated) is properly set up to obtain regularly sized firewood. Furthermore the log is automatically centred on the splitting knife set-up. The results of the experimental test showed that the firewood processor is able to produce firewood with homogeneous size and with a low production of splinters, regardless of log diameter
Modelling noise propagation generated by forest operations: a case study in Southern Italy
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
Peripheral quantitative computed tomography (pQCT) for the assessment of bone strength in most of bone affecting conditions in developmental age: a review.
Peripheral quantitative computed tomography provides an automatical scan analysis of trabecular and cortical bone compartments, calculating not only their bone mineral density (BMD), but also bone geometrical parameters, such as marrow and cortical Cross-Sectional Area (CSA), Cortical Thickness (CoTh), both periosteal and endosteal circumference, as well as biomechanical parameters like Cross-Sectional Moment of Inertia (CSMI), a measure of bending, polar moment of inertia, indicating bone strength in torsion, and Strength Strain Index (SSI). Also CSA of muscle and fat can be extracted. Muscles, which are thought to stimulate bones to adapt their geometry and mineral content, are determinant to preserve or increase bone strength; thus, pQCT provides an evaluation of the functional âmuscle-bone unitâ, defined as BMC/muscle CSA ratio. This functional approach to bone densitometry can establish if bone strength is normally adapted to the muscle force, and if muscle force is adequate for body size, providing more detailed insights to targeted strategies for the prevention and treatment of bone fragility. The present paper offers an extensive review of technical features of pQCT and its possible clinical application in the diagnostic of bone status as well as in the monitoring of the skeletonâs health follow-up
Tensile force monitoring on large winch-assist forwarders operating in British Columbia
The forest industry around the world is facing common challenges in accessing wood fiber on steep terrain. Fully mechanized harvesting systems based on specialized machines, such as winch-assist forwarders, have been specifically developed for improving the harvesting perfor- mances in steep grounds. While the mechanization process is recognized as a safety benefit, the use of cables for supporting the machine traction needs a proper investigation. Only a few studies have analyzed the cable tensile forces of winch-assist forwarders during real operations, and none of them focused on large machines normally used in North America. Consequently, a preliminary study focused on tensile force analysis of large winch-assist forwarders was conducted in three sites in the interior of British Columbia during the fall of 2017. The results report that in 86% of the cycles, the maximum working load of the cable was less than one-third of the minimum breaking load. The tensile force analysis showed an expected pattern of minimum tensile forces while the forwarders were traveling or unloading on the road site and high tensile forces when operating on steep trails, loading or traveling. Further analysis found that the maximum cycle tensile forces occurred most frequently when the machines were moving uphill, independently of whether they were empty or loaded. While the forwarders were operating on the trails, slope, travel direction, and distance of the machines from the anchor resulted statistically significant and able to account for 49% of tensile force variability. However, in the same conditions, the operator settings accounted for 77% of the tensile force variability, suggesting the human factor as the main variable in cable tensile force behavior during winch-assist operations
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