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The efficient planning and control of timber harvesting operations is crucial to growth productivity and reducing costs, and different systems or methods are applied to obtain elevated performance. In particular, cable yarding is a highly appreciated and very efficient wood extraction method in areas that are difficult to access with ground-based extraction machines. Combined logging systems are not diffuse and not often implemented. For this reason, the use and the application of innovative methods are limited. However, some combinations have recently been observed in forest operations. This study, conducted in a deciduous stand in Bulgaria, paid attention to the combination of a tractor-mounted tower yarder (Valentini V400) with a clambunk skidder (Timberjack 1010D), aiming to examine the viability and develop the operational efficiency of the two-stage extraction system and to define the time, log volume extracted per unit by the yarder and the clambunk, and the yarding and skidding costs. The researchers carried out a time-motion study and performed a regression analysis to identify those variables that are most likely to affect the duration of work elements and productivity. For cost analysis, the COST model was used. The mean productivity of the tower yarder was 10.34 m3/PMH and 8.11 m3/SMH, while for the clambunk skidder, the productivity was 6.23 m3/PMH and 4.93 m3/SMH. The net costs for the combined logging system were calculated as 120.87 €/PMH and 14.93 €/m3. This study adds new data about the correct use of both machines, supporting their application in beech forests. [ABSTRACT FROM AUTHOR]

The traditional visual tree assessment method is subjective in evaluating tree risks and therefore not effective in precisely detecting internal decay in tree trunk and root systems. To improve the accuracy of street tree risk assessment, a new nondestructive testing method was proposed. This new tree risk assessment method combines different non-destructive testing technologies, such as sonic tomography and ground-penetrating radar, which could significantly increase the accuracy of risk assessment in tree trunks and roots. The method was applied to evaluate the risk of 1,001 street trees in Shanghai's historical feature protection area. The results revealed that despite most street trees having low branch and trunk risk levels, more than one-third had high root risk levels. The risk factors of street trees were mainly in the trunk and root system, with a significant correlation between the street tree risk level and tree cavities, diseases, and insect pests, as well as the depth and range of the root distribution, leaning, and internal decay in trunks. With the help of non-destructive testing and risk assessment analysis, as well as targeted prevention measures, the possibility of street risk damage was largely reduced, including street trees tilting and collapsing during typhoons, etc. [ABSTRACT FROM AUTHOR]

The easy implementation of a nature-based solution (NBS) to address a prompt stabilisation of burnt areas may be crucial in the Mediterranean forest environment. A plot scale hydrological and ecological survey was conducted in a pine forest of the Aspromonte Massif (southern Italy) affected by a high fire severity in summer 2021. The hydrological response to 30 rainfall event groups is analysed by monitoring nine sloping plots distributed into three plot blocks (forested according to the pre-fire situation, burnt with randomly directed felled logs and burnt with manually felled logs redirected along contour lines). The hydrological response of bare soil is mitigated by about 30% through the combined effects of the NBS and the vegetation cover by pioneer species. Although the regeneration of Pinus radiata is scarcer in the arranged plots, the spontaneous vegetation, once gone, prepares better edaphic conditions for the triggering of forest dynamics assured by the auto-succession of Pinus radiata. In terms of woody mechanical resistance, NBS durability is compatible with the time required for seedlings to regenerate the forest ecosystem. The results achieved so far encourage further research on higher slopes and complementary aspects (vegetal and animal biodiversity, economic factors, etc.). [ABSTRACT FROM AUTHOR]

Cable-based yarding technology has had a long tradition on steep slopes in Europe, and the new implementation of yarding functions in recent decades favored operational efficiency and lower extraction costs. The main goal of this study was to evaluate the performance of the Syncrofalke 3t truck-mounted Processor Tower Yarder (PTY) on steep terrain, in coniferous forests managed with the shelterwood system. In particular, the aim was to determine PTY productivity and costs, with attention to parameters that could increase PTY effectiveness. The study was carried out in the Sredna Gora Mountains, Central Bulgaria, in pure Scots pine stand, with trees of average DBH = 34 cm and height = 22 m. The study was carried out in six corridors with 120 work cycles of tree extraction up the hill, 28° (53%). The mean productivity of PTY was 15.20 m3 per productive machine hour (PMH) and 12.29 m3 per scheduled machine hour (SMH) and was mainly influenced by the productivity of the yarder unit. Under the given conditions, the performance of PTY significantly increased if more than one tree (at least two trees) were attached and extracted per yarder cycle, since the productivity of the processor was approximately twice that of the yarder. The gross costs of the studied PTY were calculated at 297.48 EUR PMH−1 and 16.17 EUR m−3. The variable costs (75%) predominate in the net costs distribution, followed by the fixed costs (15%) and the labor costs (10%). The time, productivity and cost results obtained showed the high efficiency and level of integration of PTY operations in order to achieve economic efficiency of logging in montane pine forest managed in a shelterwood system. [ABSTRACT FROM AUTHOR]

Ergonomic assessment and validation are important in designing sustainable forest operations. Measurement and grading play a central role in the wood supply chain and updated solutions have started to emerge for such activities. Procuring biometric data by mobile scanning platforms has been shown to have a high potential in replacing traditional wood measurement methods, but no assessments were carried out to see if these solutions are sustainable from an ergonomics point of view. Based on more than 63 k still images, this study evaluates the working postures of three measurement options, namely, traditional measurement, scanning by a smartphone, and scanning by a commercial laser scanner. The OWAS method was used as an assessment framework to compute the postural risk indexes. A correspondence analysis was implemented to explore the association between the studied work tasks and severity of exposure, and the postural similarity of tasks was evaluated by the Canberra metric. The use of digital measurement solutions seems to be better from a postural point of view since their risk indexes were well below 200. In contrast, traditional wood measurement tasks produced postural risk indexes that were close to 250. By considering the body components, digital measurement solutions seemed to indicate a distinct postural profile. Moreover, the digital solutions stood well apart in the range of the first two action categories, indicating no urgent need for postural improvement, which was not the case for manual measurements. The main conclusion of the study is that state-of-the-art digital solutions are better from a postural point of view. For full validation, population-level studies should be carried out. [ABSTRACT FROM AUTHOR]

Agroforestry or agricultural forestry is an important resource for the exploitation of wood resources commonly based on a low level of mechanization and integrating agriculture crops land-management. Agroforestry areas consist often of buffer strip forest along the farms' boundaries or on small forest stands within the same farms. Felling is commonly based on the use of chainsaws which are used occasionally, and are often aged models and with little maintenance done on them. In this context, the present study analyzes the vibration and noise generated by chainsaws in the specific contest of the agroforestry farms. The aim is to verify the hand-arm vibrations and noise level, which self-employed agroforest operators are exposed with the occasional use of aged and rarely maintained chainsaws. The main results show that vibration exposures are significantly affected by the model and condition of use of the chainsaw and at lower level, but still significant, by the wood and the position of the handle. Regarding noise levels, the chainsaw model and condition of use also has significant effects. In summary, this study highlights that the importance of the condition of use of the chainsaw has an important effect on the vibrations and noise exposition and that these, although limited due to the limited daily use by operators, must be carefully taken into consideration, and provide for containment actions through adequate information and training. [ABSTRACT FROM AUTHOR]

Agricultural activities lead to the production of large quantities of pruning and residual biomass, the correct disposal of which is a topic of great interest. Unfortunately, although it is an environmentally unacceptable practice, disposal often takes place with uncontrolled combustion in field (open burning). Disposal using biomass boilers produces energy from controlled combustion and the use of abatement systems reduces emissions that are inevitably generated in the combustion processes of solid fuel (CO, CO2, NOx, SO2, PM, etc.). Among the pollutants produced in combustion processes, Persistent Organic Pollutants (POPs) are one of the most relevant groups of chemicals that must be monitored for their effect on human health and the environment. This paper reports the data obtained for the emissive characterization of POPs of three different wood biomass prunings (Olive, Citrus and Grapevine) focusing on VOCs, PAHs, PCBs, PCDD/Fs. Emissions samplings were performed at the stack during combustion in a 30 kWth boiler equipped with a multicyclone filter bag for PM abatement in an isokinetic mode in accordance with the CEN and ISO standards methods. Through this work, a complete emission profile of VOCs, PAHs, PCBs, and PCDD/Fs of three different biomass types is provided for the first time, showing that the use of biomass boilers produces quantities of pollutants below the regulatory limits and still lower than those produced by open burning phenomena. Citrus has shown, regarding the other two essences, elevated concentrations in terms of Σ PAH = 174.247 ng/m3, while Olive gave higher results in terms of PCBs and PCDD/Fs (respectively, 39.769 and 3390.63 TEQ pg/Nm3). This is probably due to the high concentration of iron in this biomass (711.44 mg/kg), which during combustion is a catalyst (together with copper) of PCDD/Fs. [ABSTRACT FROM AUTHOR]

The characterization of poplar wood assumes a strategic position to increase the competitiveness of the entire forest wood supply chain. From this aspect, the identification of wood quality represents a primary objective for researchers and private landowners. The quality of wood can be defined via traditional visual methods based on the experience of technicians or using traditional tools, such as incremental drills and sound hammers. The traditional properties of these traits, based only on visual characteristics, can outline a classification based on the macroscopic properties of wood with the aim of defining the volume of recoverable wood. However, this approach does not provide a good indicator of the physical or mechanical properties of wood. Mechanical tests of wood require the felling of trees with the correlated preparation of the specimens. A different solution to determine wood quality is based on the application of non-destructive technology (NDT). In this context, the aim of the present study was to determine the predictive accuracy of non-destructive analysis of the MOEd in standing trees and logs of a 22-year-old poplar clone and to examine the relationship with MOEs in sawn specimens. This relationship was also studied at three different stem heights. We non-destructively measured poplar trees and green logs using TreeSonic and Resonance Log Grader and compared the results with those obtained via a destructive method using a universal testing machine. The results showed that for clone I-214 poplar trees, the dynamic elastic moduli of standing trees and logs were validly correlated with the static elastic modulus. These results suggest that it is possible to evaluate the mechanical properties of poplar wood directly from standing trees using non-destructive techniques (NDT) and that this tool can be easily used to presort material in the forest. [ABSTRACT FROM AUTHOR]

Cable yarding remains an important option in steep terrain timber harvesting, a reason for which new or improved operational efficiency models are required to support science and practice. Developed traditionally, these models are known to require many resources, a reason for which new approaches to the problem were researched lately, mainly by the use of Global Navigation Satellite System (GNSS) data, spatial and statistical inference systems. This study evaluates the possibility of using GNSS data and machine learning techniques to classify important cable yarding events in the time domain. Three classes were assumed by the study as being relevant for cable yarding operational setup, namely carriage moving in the uphill (MU) and downhill (MD) directions, as well as carriage stopped (S). Data collected by a consumer-grade GNSS unit was processed to extract some differential parameters which were coupled with GNSS motorial and geometric features to feed a Multi-Layer Perceptron Neural Network with Back propagation (MLPNNB) in a pre-evaluation phase which aimed at mining the data structure as a strategy to develop the best MLPNNB configuration for training and testing. Leg distance, difference in elevation, speed of the carriage, and difference in heading were used together and interchangeably in this phase, based on logical assumptions. As a result of pre-evaluation, a MLPNNB using all these datasets was found to be the best scenario. Based on this outcome, the data was split into a training (70%) and a testing (30%) subset, then the MLPNNB was used to learn and generalize on these subsets. The main results indicate that the MLPNNB had an excellent performance, with a classification accuracy of 98.7, 98.4, and 98.8% in the pre-evaluation, training, and testing phases, respectively. Log-loss errors were also found to be very low (5, 5.9 and 4.1%, respectively), indicating a high generalization capability of the MLPNNB model. Based on the results, the main conclusion of the study is that original and derived GNSS data coupled with machine learning techniques could prove to be an important tool for operational monitoring and cable yarding efficiency model development, mainly due to the possibility of working with large amounts of data. [ABSTRACT FROM AUTHOR]

Research and development efforts are currently underway worldwide to examine the potential use of a wide range of non-destructive technologies (NDT) for evaluating wood and wood-based materials, from the assessment of standing trees to in-place structures. For this purpose, acoustic velocity by the Fakopp time of flight (TOF) tool was used to estimate the influence of four thinning treatments performed in Southern Italy. The objective of the study was to determine if the effects of silvicultural practices on wood quality can be identified using acoustic measurement to assess the MOEd of standing trees with non-destructive method in Calabrian pine (Pinus nigra Arnold subsp. calabrica). Four hundred and fifty standing trees from four sites were nondestructively tested using a time-of-flight acoustic wave technique. The thinning trials were conducted on 60-year-old plantations of Calabrian pine in four plots under different treatments: Control (T), light thinning (A), intermediate thinning (B) and heavy thinning (C). Statistical analysis demonstrated significant stress wave time differences between the stands with moderate thinning (A and B) and those with heavy thinning (C). The results showed that tree diameter has significant influence on acoustic wave measurements and a valid relationship exists between diameter at breast height and tree velocity. The results of these studies proved that the stress wave technique can be successfully applied on standing trees. [ABSTRACT FROM AUTHOR]

• Combustion tests were performed in a small-size biomass boiler to assess the air quality during biomass burning. • Biomass characterization and modeling of yields and emissions in combustion. • Evaluation of woodfuel parameters useful to sustainable practices, highest energetic yields and lowest environmental impacts. • Olive residues represents the most advantageous biomass, in terms of emissions and energy yield. • Grapevine and citrus residues showed high N content and consequent high NO x production. The increased interest in using farm-grown biomass for energy production makes it necessary to expand and deepen knowledge on combustion of agricultural residues. The lack of data and studies on solid fuel quality, and combustion related emissions, represents an obstacle to the sustainable development of agricultural biomass industry. In the Mediterranean basin, large quantities of lignocellulosic biomass are obtained yearly from pruning operations carried out largely widespread in fruit plantations such as citrus, grapevine and olive orchards. The most common practice to eliminate this type of residue is the open burning, carried out directly on the field by farmers, without any emissions control or energy recovery. The aim of this study was to obtain a clear description of three different wood biomasses and their behavior during combustion. The physicochemical properties were studied to determine their influence on combustion emissions. Measurements were conducted in laboratory and subsequently carbon monoxide (CO), carbon dioxide (CO 2), oxygen (O 2), nitrogen oxides (NO x), sulfur dioxide (SO 2), Total Organic Compounds (TOC), and particulate matter (PM) emissions were evaluated during combustion in a 30 kW boiler equipped with a multicyclone filter bags for emission abatement. Principal Component Analysis (PCA) was applied to the data of biomass properties and emissions parameters in order to elucidate which feedstock features had a more determinant influence on the combustion process. Grapevine and citrus showed high N content and consequent high NO x production. Olive highlighted the best characteristics, high energetic potential and low emissions under regulation limits; in addition, olive pruning residues is the most available woodfuel in the Mediterranean area of Europe, confirming its great potential on agricultural biomass industry sustainable development. [ABSTRACT FROM AUTHOR]

Steep terrain harvesting can only be implemented by a limited set of operational alternatives; therefore, it is important to be efficient in such conditions, in order to avoid incurring high costs. Harvesting abiotically-disturbed forests (salvage harvests caused by wet snow), which is becoming common these days, can significantly impact the operational efficiency of extraction operations. This study was implemented in order to evaluate the performance of truck-mounted uphill cable yarding operations in salvage logging deployed in coniferous stands. A time study was used to estimate the productivity and yarding costs, and predictive models were developed in order to relate the time consumption and productivity to the relevant operational factors, including the degree of wood damage. The average operational conditions were characterized by an extraction distance of 101 m and a lateral yarding distance of 18 m, resulting in a productivity rate of 20.1 m3 h−1. In response to different kind of delays, the productivity rate decreased to 12.8 m3 h−1. Under the prevailing conditions, lateral yarding accounted for 32% of the gross work cycle time, and for 50% of the delay-free work cycle time of the machine. Decreasing the lateral yarding distance and increasing the payload volume to the maximum capacity of the machine would eventually lead to a yarding productivity of close to 30 m3 per SMH (scheduled machine hour). The calculation of the gross costs of uphill yarding showed that the labor costs (35.7%) were slightly higher than the fixed costs (32.9%), and twice as high compared to the variable costs (17.7%). The remote control of the carriage, mechanical slack-pulling mechanisms, and radio-controlled chokers are just some of the improvements that would have led to increments in operational efficiency. [ABSTRACT FROM AUTHOR]

The production of wood pellets has grown considerably in the last decades. Besides woody biomass, other feedstocks can be used for pellet production. Among these, miscanthus presents some advantages because, even if specifically cultivated, it requires low inputs such as fertilisers and pesticides and shows high biomass yield (up to 28 tons of dry matter ha−1 in Europe). Even if in the last years some studies evaluated the environmental impact of woody pellet production, there is no information about the environmental performances of miscanthus pellet production. In this study, the environmental impact of miscanthus pellet was evaluated using the Life Cycle Assessment approach with a cradle-to plant gate perspective. Primary data were collected in a small-medium size pelletizing plant located in Northern Italy where miscanthus is cultivated to be directly processed. The results highlight how the miscanthus pellet shows lower environmental impact compared to woody pellet, mainly due to the lower energy consumption during pelletizing. The possibility to pelletize the miscanthus biomass without any drying offsets the environmental impact related to the miscanthus cultivation for all the evaluated impact categories (except for Marine eutrophication). In detail, for global warming potential, 1 ton of miscanthus pellet shows an impact of 121.6 kg CO2 eq. (about 8% lower respect to woody pellet) while for the other evaluated impact categories the impact reduction ranges from 4 to 59%. Harvesting, which unlike the other field operations is carried out every year, is by far the main contributor to the impacts of the cultivation phase while electricity is the main contributor to the pelletizing phase. [ABSTRACT FROM AUTHOR]

In the middle of XIX century, Calabrian pine was planted in southern Italy to increase the forest cover in mountainous areas. Many of these forest stands were never managed, since they were considered non-profitable for wood production. Therefore, in order to promote timber value, it is fundamental to study, more deeply, the characteristics and management options for this species. The acoustic technologies applied to predict the mechanical and physical properties of timber are well-established practices in forest research. In this study, we hypothesized that the tree stand density could influence the dynamic modulus of elasticity (MOEd) and, therefore, the future wood quality. We specifically aimed to verify if different management options, when applied, could influence the timber quality of Calabrian pine growing in similar environmental conditions. The study was conducted in the Aspromonte National Park (Calabria, Southern Italy). We derived the MOEd values from data obtained by the acoustic velocity measured through the TreeSonic™ timer. Calabrian pine trees were selected in stands where different intensities of thinning were applied eleven years before this study began (no thinning, thinning 25%, thinning 50%, and thinning 75%). The percentage refers to the number of trees cut with respect to the total number of occurring trees. The analyses were conducted on a total of 804 trees (201 trees for each intensity of thinning). A strong positive correlation was observed between the acoustic velocity, the thinning treatments and diameter at breast height (DBH). The thinning realized at 25% induced better tree wood quality. We also analyzed the best predictors for MOEd estimation, using variables easily measurable in the field, such as tree diameter, tree height, or their transformations (number of trees per hectare, basal area per hectare). We provide, here, a useful tool for predicting the wood stiffness in relation to stand parameters easily measurable in forest inventories. [ABSTRACT FROM AUTHOR]