Harvesting systems and technologies
Forest biomass and carbon sequestration
Forest road network planning, management and construction
System organization and forest operations
IT technologies and remote sensing
Engineering in urban forestry
Vehicle/machine design and evaluation
Modelling and sustainable management
Eco-efficient technologies in forestry
Ergonomics and work safety
volume: 39, issue: 1
In the study, the relationship between operators’ age, experience and mechanized cut-to-length
(CTL) harvesting productivity was examined. The data were five-year follow-up data from 28
operators and 38 CTL harvesters collected from southern Finland. Productivities were converted
to relative productivities and average productivity models were created. Case specific
productivities were compared to modelled values, and productivity ratio models including
separate lower and upper quartile models were produced.
The relative productivity of operators at the age of 45 years in clear cuttings was 17.8%
higher and in thinnings 14.9% higher than that of operators at the age of 25 years. The relative
lower quartile productivity increased from operators aged 25 to operators aged 45 years by
38.6% in clear cuttings and 29.4% in thinnings. The relative productivity of operators having
experience of 20 years was 23.6% higher in clear cuttings and 16.2% higher in thinnings than
that of operators having experience of 3 years. Operators’ experience of 20 years produced
43.1% better lower quartile relative productivity in clear cuttings and 29.1% in thinnings
compared to 3 years’ experience. The relative upper quartile productivity was 5.7% higher in
clear cuttings for operators aged 45 years than for operators aged 25 years, but otherwise, there
was no statistical correlation between upper quartile productivity and age or experience.
As a conclusion, CTL harvester operators’ average productivity increases slowly after the
initial learning phase up to 15 years of experience. The peak productivity was uncorrelated to
age or experience, but the experience raised the bottom productivity values.
volume: 39, issue: 1
Within the fuel wood supply chain, comminution and transport have been identified as processes
with the highest costs, energy consumption and emissions. The coordination of comminution
and transport aimed at avoiding operational delays is also complex. Nevertheless,
the use of forest biomass helps to reduce the effects of climate change and produces an additional
income, especially in rural areas. About 20 years ago, at the beginning of the industrial
forest fuel utilisation, the focus of the research was on developing and analysing adequate
supply chains and machines. Nowadays, as state-of-the-art systems have been established, the
focus is on improving the efficiency of the processes and the quality of the products. This paper
provides a review of research trends of the last ten years focusing on comminution and transport
of forest biomass in Europe.
Comminution should become more efficient by analysing the effects of wood characteristics on
chipper performance and product quality, by tailoring chipper configuration according to those
findings and by introducing mechanical devices for improving the quality of chips. Transport
processes have the potential to become more efficient if the configuration of trucks is adapted
according to operational and legal requirements, and when considering moisture content
management. Finally, economic and environmental assessment of supply chains was made by
several studies. Future research is expected to focus on customizing the product quality according
to user’s requirements and on optimising the coordination of chipper and truck by
simulation and automatization tools.
volume: 39, issue: 2
This paper discusses the key issues of forestry workers training in Croatia, especially dealing
with the providers of vocational training, their profile, training procedures and measures
necessary for training improvement. A combined approach of literature review, internet search
and questionnaire of training providers was applied in order to collect data on training programs
conducted in Croatia. The research was conducted during 2016, and it included 94
legal entities authorized for occupational safety training in the Republic of Croatia, with respect
to safe working practice training and vocational training for operating machinery (chainsaw
and/or skidder). The analysis used basic descriptive statistics.
Research results showed that 30.85% of the analyzed legal entities provide only training for
safe working practice, 15.96% provide both trainings – safe work practice and vocational
training for operating machinery, 5.32% of the analyzed entities provide only vocational
training for operating machinery, 31.91% do not carry out any form of training in forestry,
while 15.96% refused to answer questions. On the other hand, 15.56% of the legal entities,
which do not carry out any training or did not answer these questions, have on their official
website services posted for vocational training in operating machinery (chainsaw and/or skidder).
The key findings of the conducted research have pointed out the great heterogeneity
amongst providers of forestry workers training, and certain reductions or limitations in the
current training programs, both from the aspect of duration of the theoretical and practical
training, and the use of non-transparent criteria and standards in the assessment of training.
As an example of successful solution in forestry workers training, European Chainsaw Standard
model (ECS) is shortly presented in the paper. Discussion and conclusion sections provide
an overview of legislative and organizational requirements for the application of previously
developed European model (ECS) in developing the certification system for training of forestry
workers in Croatia.
volume: 39, issue: 2
Economic analysis of even-aged fir stand management was illustrated using the example of the
forests of the Croatian Dinaric region, as well as their transformation into more stable unevenaged
structures. Two scenarios (even-aged, uneven-aged) were simulated against the backdrop
of the existing forest stand structure of future forest stand management during a 140-year
period using forest growth modeling software MOSES version 3.0 in order to identify economic
differences amongst different scenarios both at stand level and at forest level. The research
included forest management analysis throughout the transformation period and subsequently
the continuation of balanced state forest management. Moreover, the research also
provided the opportunity of forest purchase within the price range from 1000 to 12,500 EUR/ha,
amid assumed fluctuation of selling prices of timber assortments throughout the simulation
period. Discount rates from 1% to 5% were used during the economic analysis. The research
findings showed that, according to harvesting costs, Net Present Value and Internal Rate of
Return, uneven-aged forest management system, including the transformation period, achieved
superior economic results, albeit at discount rates that exceeded 1.24%. The conclusion was
reached that, according to all economic criteria, uneven-aged mixed silver fir-beech management
system is preferred compared with the pure even-aged silver fir management.
volume: 40, issue: 1
The purpose of this paper is to assess the delivered cost of pulpwood from natural hardwood
stands in the State of Tennessee using forest operations supply chain analysis. The study is
based on primary production and equipment data collected from logging firms using a statewide
in-depth harvesting and transportation survey. Survey results were used to develop estimates
for the delivery cost of hardwood pulpwood removed per green tonne unit hour. Findings
revealed not only the variability of inputs attached to costing harvesting operations, but
also the difficulty in identifying one typical harvest system for the state. This may be explained
by the very diverse operating conditions and systems, as well as the low stumpage prices and
high cost of harvesting and delivery that are predominantly managed by small scale operations.
Results have shown that the cost of harvesting a tonne of wood for a distance of up to 50 km
ranges from an average minimum of $43 per tonne to an average maximum of $51 per tonne.
After this distance, the cost increases exponentially. The fact that this study is the first for the
state that looks at the operations logistics indicates the lack of available knowledge of the true
cost incurred by operators that may have a lasting impact not only on the continuity of logging
operations but also the sustainability and availability of forest products and workforce.
volume: 40, issue: 1
Private forests in Croatia, Bosnia and Herzegovina and Serbia are highly fragmented into
small plots of land with low productivity level and a large number of owners. Nevertheless,
they are recognized in the strategic plans and programs concerning renewable energy as having
a significant potential for woody biomass production. A regional research was conducted
among 350 private forest owners in each of the three South-East European countries, Bosnia
and Herzegovina, Croatia, and Serbia. It analyzed management activities and readiness of
private forest owners to produce additional quantities of woody biomass. Smart regulation
principles were selected as analytical framework in order to understand how the design of
forest policy instruments, based on specific characteristics of the target groups, can contribute
to the improvement of private forest owners’ readiness to mobilize additional quantities of
woody biomass from their forests. The results of this research indicated that although the
majority of private forest owners use their forests for producing firewood to meet their own
needs – 91.2% of private forest owners in Croatia, 85.0% in Bosnia and Herzegovina and
89.7% in Serbia, there is economic interest of private forest owners to produce additional
quantities of woody biomass beyond their own fuelwood household consumption – 43.9% in
Croatia, 45.8% in Bosnia and Herzegovina and 54.8% in Serbia. Moreover, private forest
owners’ socio-demographic characteristics, forest property characteristics and management
objectives significantly impacted the owners’ readiness to produce additional quantities of
woody biomass. The readiness for woody biomass mobilization could be increased by providing
different policy instruments, since this is deemed important by private forest owners. Hence,
forest policy recommendations were proposed that may support the private forest owners’
readiness to produce additional quantities of woody biomass.
volume: 41, issue: 1
The improvement of harvesting methodologies plays an important role in the optimization of wood production in a context of sustainable forest management. Different harvesting methods can be applied according to forest site-specific condition and the appropriate mechanization level depends on a number of factors. Therefore, efficiency and functionality of wood harvesting operations depend on several factors. The aim of this study is to analyze how the different harvesting processes affect operational costs and labor productivity in typical small-scale Italian harvesting companies. A multiple linear regression model (MLR) and artificial neural network (ANN) have been carried out to predict gross time, productivity and costs estimation in a series of qualitative and quantitative variables. The results have created a correct statistical model able to accurately estimate the technical parameters (work time and productivity) and economic parameters (costs per unit of product and per hectare) useful to the forestry entrepreneur to predict the results of the work in advance, considering only the values detectable of some characteristic elements of the worksite.
volume: 41, issue: 1
Upon carrying out logging, residues remain in the cutting area. Logging residues are an additional source of wood raw material for the production of fuel chips to be used in bioenergetics. In order to plan the logging residues collection and processing technology, it is necessary to gather information on the amount of this type of waste and its distribution within the cutting area.
The article deals with the line intersect (LIS) method.
The aim of this article was to assess the accuracy of the LIS method for quantifying logging residues after cut-to-length logging (CTL), uniformly distributed within the technology traffic lanes (strips) of width b on the cutting area of arbitrary shape S.
The studies were conducted using computer simulations. In the models, logging residues are represented as clusters in the form of circles. The laws of distribution of the radius of the clusters and their position in the plot were determined by field measurements.
In the simulations, clusters uniformly distributed along the X-axis and stripes on the Y-axis were considered. The samples of lines were the set of lines of different length and mutually perpendicular and parallel to the coordinate axes X, Y.
In the simulations, four types of stripes were considered with a different angle to the Y-axis. Type 1 – angle = 0°, type 2 – angle = 15°, type 3 angle = 30°, type 4 – angle = 45°.
It was determined through simulation that the estimated mean radius of the clusters is greater by 24% than the true mean radius.
The LIS method formula is appropriate for estimating the amount of forest residues after CTL logging provided the true mean radius is taken. According to the results of simulation experiments, it was found that the results are in good agreement with the theoretical formulas if the location of the sample lines is mutually perpendicular and parallel to the coordinate axes X, Y of the area. Differences remain within the limits of 20% error
volume: 41, issue: 1
Forwarding can be divided into separate work elements. These are affected by several factors: forwarding distance, load volume, and types of assortments harvested. For a detailed planning of thinning, productivity models should include these factors. This study analysed the time consumption of forwarder thinning operations in five pine plantations in the north-east of Argentina, determining how the log size and log concentration affect each work element. Time-and-motion studies were carried out, recording the activities with digital video cameras, and tracking the forwarder movements with global navigation satellite system (GNSS) receivers. Different linear mixed models were fitted to estimate the time consumption of each work element in relation to different predictive factors. When driving on the road, the forwarders had an average speed of 71.6 m min-1 empty and 75.7 m min-1 loaded. When driving in the stand, the average speed was 56.9 m min-1 empty and 52.2 m min-1 loaded. These speeds did not correlate with the forwarder size or load volume. For the loading and unloading elements, the linear mixed model explained 56% and 49% of the variability considering only the fixed effect of the logs size and the load volume. For driving while loading, the total volume loaded, and the log concentration of the assortment loaded explained 50% of the time consumption variability, with 17% being explained by random effects. The general time and productivity model developed can be applied to support accurate decisions in the process of thinning planning.
volume: 41, issue: 1
The great complexity of the operation of wood harvesting machines and unpredictable differences of performance between operators must be reflected in the industry recruitment techniques. This work aimed to carry out an evaluation of the bimanual motor skill in candidates for the position of harvester operators using a virtual reality simulator to generate information that can contribute to and improve the selection process. The work was developed at the Forest Operators Training Center (CENFOR), at the State University of the Center–West, in Irati, PR. A sample of 12 individuals was studied and distributed into three levels of performance. The motor ability of the individuals was evaluated through the variables: »run time«, »fall direction«, and »cutting height«, assessed at different points during a 4-hour practice – 0.5; 1.0; 1.5; 2.0; 3.0 and 4.0 hours – practice in a virtual harvester simulator. The data were analyzed by variance and means, as well as compared to a Tukey test at the 5% level of significance. The individuals had a significant difference in the variables »run time« and »cutting height«, and could be accurately used to predict bimanual motor skill/performance. There was a significant gain in the performance of the operators up to 1.5 hours after the beginning of the skill test, and all those who demonstrated greater and lesser ability in the first half hour of the test maintained this behavior until the end of the training period. The virtual reality simulator can be used as a tool to assess bimanual motor skills during the selection of harvester operators.
volume: 41, issue:
Biomass collection could contribute to the reduction of wildfire prevention costs by obtaining solid biofuels from shrublands that pose a high fire risk, using mechanical harvesting methods that have not been sufficiently tested in shrub formations. The objective of this study is to evaluate the performance of a harvester-baler system (Biobaler WB55) for collecting rockrose (Cistus laurifolius L.) shrublands biomass, to asses the influence of the cutting rotor tool (blades or hammers) on weight and surface productivities and operating costs, as well as to determine the influence of the standing shrub biomass load on productivity and biomass collection efficiency.
A 31-hour test was conducted on 21 ha of a typical Mediterranean shrubland in the centre of Spain. Data collection included time study, daily collected area, fuel consumption and bale measurements. Samples of fresh biomass from bales were collected for the determination of moisture content. The average collected biomass was 2.3 tDM·ha-1 (tonnes of dry matter per hectare), with an average productivity of 1.6 tDM·PMH-1 and an average yield of 0.7 ha·PMH-1. Better results were obtained with blades than with hammers in the cutting rotor tool (35% more collected biomass, 42% higher weight productivity, 61% higher collection efficiency and 14% greater surface productivity). The average harvest-baling costs with blades were estimated at 99.5 €∙PMH-1, 142.1 €∙ha-1 and 53.9 €∙tDM-1 (34.0 €∙tWM-1, € per tonne of wet matter), and with hammers 91.5 €∙PMH-1, 152.5 €∙ha-1 and 81.4 €∙tDM-1 (51.1 €∙tWM-1).
The analysed harvester-baler was operated without difficulty in this type of vegetation and was able to collect up to 31% of the shrub biomass load in the study area. The amount of uncollected biomass and the decrease in biomass collection efficiency, as shrub biomass load increases, suggest that possible mechanical improvements are needed to improve biomass collection efficiency.
volume: 41, issue:
In tactical forest management planning, the decisions required to meet the strategic plan are made, and these include: i) scheduling of spatially explicit harvest-blocks; ii) construction of a road-network required to access these blocks; and iii) transportation costs within the tactical forest planning area (hereafter only referred to as transportation costs) that emerge from the first two decisions. These three decisions are interdependent and should therefore be integrated in any optimization model. At present, this integration is not fully made. This is because: i) the integrated model is NP-hard, and exact solutions are not feasible for large and medium-sized forests; and ii) metaheuristic search algorithms, which can be used on larger forests, have not integrated transportation costs realistically.
The economic consequences of not integrating transportation costs into tactical planning models has not been quantified and evaluated by researchers; and the objective of this paper is to fill this gap in knowledge. To this end, an exact solution approach is used to solve and compare two integrated models: i) a model in which transportation costs are included in the objective function, and b) a model in which transportation costs are excluded from the objective function. The models were applied to three forests ranging in area from 6628 to 19,677 ha.
Results show that: i) the model which included transportation costs yielded solutions with major reductions in both transportation and total costs; and ii) that, as the forests to which the model was applied tripled in area (from 6628 ha to 19,677 ha), the percent reduction in total costs increased disproportionately – more than fivefold (from 3.9% to 21%). These results are important, for they indicate that the integration of transportation costs into a tactical planning model is of major economic consequence.
volume: 42, issue:
This paper offers a conceptual analysis of the unaccounted-for cost of owning and operating used machines from an operational, financial and market perspective. It is based on input from experts and a literature review. In the scientific literature, assessing the operating cost of used machines in forest operations is typically based on standard cost assessment methods using costing/pricing input from similar unused machines. This is the case since there are usually no historical data for observed used machines available to analyze. This substitute analysis is problematic to many used and depreciated machines owners. The changing trends in forest technology attest that old machinery do not hold to the same input cost data variables or values of new machines. In fact, they belong to two rather competing different markets: (used vs. new equipment markets). With the technological, market and machinery regulations and dynamic changes, the substitute cost analysis is not representative. Better data is required to understand the cost of owning and operating used machines and the justification is the focal point of this paper. The outcome of the expert and literature analysis in this paper demonstrates that a broader understanding of the cost of a used machine is required and doable. A proposed understanding integrates the machine availability (performance), cost factors (financial) and market evaluation (price), in isolation (single piece of machine) as well as in a fleet, to assess a used machine ownership cost. The study is intended to offer forest machine operators, owners, scientists, and practitioners a proposed new approach to value used machines and further investigations and data inputs required to make used machines costing methods more relevant.
volume: 42, issue:
Logistics of roundwood and biomass comprise a high number of operations, machinery, storage sites and transportable roundwood and biomass assortments. Moreover, complex and highly varying operational environment through the year poses logistics challenges incurring additional costs. An extensive review of studies was conducted in Sweden and Finland concerning roundwood and biomass logistics, starting from roadside landings and ending with delivery to a mill or a conversion facility. The main aim of the review was to describe trends in roundwood and biomass logistics since the start of the century. Papers were classified to categories of truck transports and roads, terminals, multimodal transports, storage and supply chain logistics. Slightly over 50% of reviewed articles were constrained to biomass only, 31% to roundwood only and 14% to both. Rapid technology development, amendments concerning road transports, increasing environmental concerns and forestry sector’s push to decrease the logistics costs can be seen as the biggest drivers for the reviewed studies and their study objectives. These aspects will also drive and increase the demand for research and development in roundwood and biomass logistics in the future.
volume: 42, issue:
Skilled contractors are needed to meet the increased demand for wood and to maintain a competitive edge in forestry. The structure of the forest industry has changed significantly. Today’s situation favours smaller contractors that are more flexible. Worldwide contractors are important for forest operations, but there is often limited knowledge about how well they fulfil demands about resource efficiency, social responsibility and environmental protection. The aim of this paper is to present the guidelines for the assessment of forestry contractors following sustainability principles and to present a recently developed system. In addition to the requirements for professional competences and legislative obligations, the system proposes a number of additional requirements such as corporate social responsibility, participation in the local community and greater environmental responsibility. The forestry contractor and the certification body sign a cooperation agreement to obtain the expert assessment. The expert assessment is performed by an evaluator authorised by a certification body. A web service has been introduced with the purpose of serving as a communication tool between professional evaluators and forestry contractors, as well as providing a new possibility for forest owners to get direct contact with forestry contractors. The system enables its users to exert influence on the assessment of forestry contractors by assessing the quality of their services. Private forests would greatly benefit from customer feedback information on the service quality. By now, 1584 forest contractors have registered in Slovenia, where 67% provide the service of cutting and skidding, 8% provide woodchipper service, 7% transport of round wood, 5% cable crane yarding and 4% fully mechanised harvesting. Until June 2020, 142 forest contractors have gone through the process of quality assessment.
volume: 42, issue:
As mechanization increases, the percentage of the total cost of the logging operation due to equipment purchase and operation increases. This makes assumptions about machine life, machine maintenance costs, and fuel consumption more critical in understanding the costs of logging operations. For many years machine rate calculations have followed a fixed format based on the concept of scheduled and productive machine hours. When equipment utilization is less than 100%, the traditional machine rate calculation assumes that the machine continues to depreciate and machine wear occurs during the non-productive time at the same rate as during the productive time. This can lead to overestimates of the hourly cost of machine operation by effectively shortening the machine lifetime productive hours as the utilization decreases. The use of inflated machine rates can distort comparisons of logging systems, logging strategies, equipment replacement strategies, and perhaps the viability of a logging operation. We propose adjusting the life of the machine to account for non-productive time: machine life in years should be increased with a decrease in machine utilization, while cumulative machine life in hours remains the same. Once the life has been adjusted, the traditional machine rate calculation procedure can be carried out as is normally done. We provided an example that shows the traditional method at 50% utilization yielded a machine rate per productive hour nearly 30% higher than our modified method. Our sample analysis showed the traditional method consistently provided overestimates for any utilization rate less than 100%, with lower utilization rates yielding progressively increasing overestimates. We believe that our modified approach yields more accurate estimates of machine costs that would contribute to an improved understanding of the machine costs of forest operations.
volume: 43, issue:
Despite the extensive use of cut-to-length mechanized systems, harvester data remains largely underutilized by most stakeholders in Germany. Therefore, the goal of this study was to determine how business processes should be restructured to allow for a continuous use of forest machine data, with the main focus on harvester production data, along the German wood supply chain. We also wanted to identify possible benefits and challenges of the restructuring through a qualitative analysis of the newly designed business process. The Bavarian State Forest Enterprise was chosen for a case study approach. Based on expert interviews, the current and to-be processes were modeled. Results obtained from the qualitative data indicated that an integration of harvester data is achievable in Germany. Harvester data from forest operations can be provided to all subsequent activities along the supply chain. Core changes were the addition of a digital work order, the data exchange between harvester and forwarder, the pile order and the exchange of production data. Benefits for every stakeholder were determined. Through the reengineered process, harvesting and timber information are available and known at an earlier stage of the process, throughput information stations could be eliminated and working comfort could be improved. Ecological benefits could also be achieved through an anticipated reduction of CO2 emissions and protection of sensitive nature areas. Negative consequences of harvester data integration could appear in the social sphere and were in line with the reduction of personal contact. Challenges for the implementation in reality, besides the legal situation, could be the availability of on-board computers in forwarders, cost for new IT applications, willingness of stakeholders to cooperate and availability of internet access. Further research should be focused on the combination of harvester data with other data types and the practical implementation of the TB process.
volume: 43, issue:
In this paper, we introduce a Microsoft Excel Workbook containing the software Equipment Selection Problem DS (ESPDS) that recognizes the special structure of the equipment selection problem. The ESPDS approach is based on the context of the Brazilian forestry sector using detailed equipment maintenance schedules. No special restrictions are needed on cost inputs over time or technologies. The output is an equipment schedule that can be used to project equipment investment needs, operational costs, and tree harvesting costs. ESPDS can be applied to support companies and contractors in order to choose the best option for their operations, as well as to achieve better equipment purchase agreements. We will show how ESPDS will also be useful in providing longer term estimates of production costs. The sensitivity analysis shows how different inputs and maintenance polices can affect the best alternative. A numerical example is included considering the entrance of a specific technology that increases the equipment productivity in order to examine whether it can change the solution. ESPDS is intuitive, flexible, and easy to calculate. Although designed for the forestry industry, the approach is readily transferable to other sectors. ESPDS may be found on the web at the following URL: https://www.researchgate.net/publication/350811380_ESPDS_workbook.
volume: 43, issue:
The chainsaw, as a work equipment, is considered one of the most dangerous in the field of occupational health and safety. The chainsaw is especially used in the forestry sector, although it is also used in other different sectors such as agriculture, construction or gardening. This study was carried out using an ad-hoc questionnaire as a research tool in order to assess the weaknesses in the training received by workers who use chainsaws in Andalusia, Spain, since it has never been addressed before. To achieve the objective set, the questionnaire was completed by 378 operators working with chainsaw and their responses were analysed. The results of this study show that there are obvious shortcomings related to work with chainsaws in very significant aspects for the occupational health and safety. Of special importance is the lack of training detected on rescue techniques and work at height, since these are aspects of special risk for workers’ health that could cause accidents with severe injuries. Also, a common denominator in all aspects studied was the lack of safety inspections and the state of the equipment to be used. These results evidence that there is a need to regulate chainsaw operator training.
volume: 43, issue:
Cable-based technologies have been the backbone of forest management and harvesting on steep slopes for decades. The design of a cable road is a complex task. It essentially comprises the identification of the start and end points of a cable road, as well as the intermediate supports. With the aim of simplifying this design process, we developed a semi-automated cable road design tool (QGIS plugin SEILAPLAN) that is easy and intuitive to use. SEILAPLAN is based on mechanical assumptions for the structural analysis that are »close-to-reality«, contains an algorithm that checks all possible intermediate support combinations and automatically identifies the optimal solution, and integrates tools and geodata within a GIS application. We present its main components and present an example of application. The integration into a GIS program, the implemented cable mechanics, and the associated information for the construction of a cable road were highly appreciated by the users.
volume: 43, issue:
Legislation and policy makers have recognized private forest owners cooperation in machinery ring as an instrument to support wood mobilization through efficient use of machinery. The study analyzes private forest owner's cooperation in the machinery ring in Slovenia and determines whether this cooperation contributes to wood mobilization from small-scale private forests. The research was conducted in two phases. In the first phase, the survey was conducted among the members of machinery rings at their annual general meetings (24 machinery rings participated in the survey, representing 64.9% of the total number of machinery rings). The questionnaire was distributed to all members present at the annual general meetings (n=529) and only those who were private forest owner or provided services within machinery rings were eligible to complete the questionnaire (n=438). In the second phase, data on the amount of service provided by machinery ring members were compared with the amount of felling in private forests for 2019 to gain insight into the extend of forestry work (timber harvesting) carried out in a private forest under neighbourhood assistance.The results show that machinery rings members are predominantly male, on average 50 years old, mainly with high school education and occupation in agriculture, owning on average 15.2 ha of forest. Regardless of forest management activities, machinery ring members perform forest management activities in their forest by themselves or with the help of family members. Only a small proportion of members use neighbourhood assistance to carry out the work. This most often occurs in the transport of timber. A very small proportion of members provide forest services through the machinery ring, but their scope of services is not insignificant. In 2019, machinery ring members most often performed harvesting activities with the chain saw, followed by timber skidding as a service. Equipment with machinery for providing services is good among members – about three quarters of them have a chainsaw and an adapted agricultural tractor, but this machinery is quite old, showing that machinery is insufficiently used for forestry operations. The results show that machinery rings are nowadays an essential part of strategic (operational) management in Slovenian agriculture and forestry, and provide important insights into the possibilities to improve forestry operations and the future development cooperation between private forest owners in machinery rings to support wood mobilization from small-scale private forests.
volume: 43, issue:
Work safety in the forestry industry, where chainsaws are used for tree felling, continues to be a top priority. The mobility of workers involved in chainsaw operations between Europe and Asia has become more common in today’s global workplace. Therefore, sharing knowledge about the types of work safety issues found in both regions can be beneficial. Increased knowledge and safety awareness in the workplace can contribute to a reduction in chainsaw accidents. This paper identifies and addresses four key related areas, namely: regulatory frameworks; chainsaw accidents; personal protective equipment and chainsaw training. Information for both regions was evaluated via interviews, questionnaires, direct observation, desk studies, field studies and descriptive statistical analysis. A total of 234 participants responded to the main research questionnaire, which resulted in data analysis of significant questions related to the use of personal protective equipment (PPE) and possible causes of accidents. Key findings included a need for more information relating to the effect of regulations in individual countries and chainsaw accident and fatality statistics within Asia. A requirement for further research into the suitability of PPE used in Asia was identified. Inadequate training was seen as a primary factor causing accidents in Asia, while in Europe, it was due to chainsaw operators taking shortcuts. Inadequate workplace supervision and a lack of uniform and affordable training provision were common issues identified within both regions. Field tests carried out in accordance with the International/European chainsaw (ICC/ECC) qualification standards of the »non-profit« Awarding Body Association (ABA) International were successful in demonstrating the benefits of uniform training to participants in Europe and Asia. Overall, the study raises awareness of the fatal consequences of risk-taking behaviour to work safety, requiring a better understanding of the problem from a social psychology perspective. It identifies the self-employed or temporary worker groups as high-risk categories in both regions, with younger workers seen to be more at risk of injury in Asia and older workers more at risk in Europe. The findings demonstrate that, while there are differences between the two regions (at least within the participating countries), it is essential to provide quality education and raise skills by training and promotion of supervision in order to prevent chainsaw accidents. This can lead to the development of the building blocks of a holistic approach to safety in forestry work, which, as shown in this paper, can result in a decrease in the occurrence of accidents.
volume: 43, issue:
The forestry sector is facing critical challenges due to climate change. Decision-making support based on efficiency evaluation using non-parametric methods could provide important information for both forest managers and policymakers. However, such advanced technical analysis is scarce in forestry science. When applied, its application has been primarily based on aggregated, macro-level data, and efficiency was analysed for the forestry sector as a whole. There is a lack of studies from the company-level perspective, which are needed to provide sound decision support.
In this paper, we focus on the micro-data level and offer the data envelopment analysis model settings and interpretations for an efficiency evaluation based on the financial data of individual forestry companies. The aim is to provide an original analysis of the company-level driving forces of forestry sector efficiency. The results for central European countries show that efficiency is driven by company size and country of operation. The study also confirms that, generally, German companies are the »efficiency leaders« in the region, while Czech companies may serve as an efficiency reference for east-central European forestry companies.
volume: 44, issue:
Coppices are a major potential source of forest biomass in Spain, where they occupy around 4M ha. Quercus coppices are mostly neglected because of their high harvesting costs and the small size of their products. This makes them very interesting to test and compare alternative means for utilizing their resources in an optimized way. Hence, a comparative study of motor-manual and mechanized felling and bunching was conducted when thinning dense coppice stands of the two most important oak species in Spain to obtain biomass for bioenergy use. In particular, the study matched chainsaw felling and manual piling against the work of a drive-to-tree feller-buncher previously analyzed in the very same sites. Productivity functions for motor-manual felling and piling were fitted for each species. The derived unit cost functions show that the felling-bunching costs are lower for the motor-manual option in stands of both species, particularly for the smaller tree sizes. Nevertheless, when the strongly reduced loading times in forwarding associated to the mechanization are taken into account, the total harvesting cost is often lower for the mechanized option. That is true for all tree sizes of Q. ilex, and for trees larger than 13 cm diameter at breast height (DBH) for Q. pyrenaica. Residual stand damage was low to moderate, but always significantly greater for the mechanized option compared with the motormanual one. Soil damage was very low for both alternatives. The stumps experimented significantly greater damages in the mechanized felling and bunching, but further research is needed to determine if those damages have any impact on stump mortality, sprouting capability and future plants vigor. The greater productivity and level of tree damages found in Q. ilex when compared to Q. pyrenaica are likely due to the narrower and lighter crown of the latter.
volume: 44, issue:
Urbanization, shrinking markets, and reduced forestry investment may affect harvesting efficiency in regions of the US South. To monitor these conditions, logging businesses have been tracked by surveys conducted by universities and trade associations. This project used a sampling approach coordinated with FIA utilization studies to sample logging crews based on a harvesting location. The approach was used to develop relationships among firm attributes and site attributes in six southeastern states (AL, GA, FL, NC, SC, and VA) from 2011 to 2018. The data included harvest attributes (location, harvest size and stand type) and logging firm attributes (production, crew labor, crew number, the number of machines by type, and machine age). For crew capital value, an equation was developed for this study using machine number and average machine age. The data from logging crews on 419 harvests were analyzed by region, harvest size, and stand type. Mean values for crew labor ranged from 3.1 to 7.1 workers. The average capital value per crew ranged from $220,000 to $524,000 per crew in the Coastal Plain with a narrower range in the Piedmont. In the Coastal Plain, higher productivity was detected for larger harvests and pine versus hardwood and mixed stands; however, in the Piedmont those trends were less obvious. Ratio of feller-bunchers, skidders and loaders were mostly 1:1:1 or 1:2:1 with 41% and 24% of samples, respectively. There were notable trends among Coastal Plain loggers regarding capital value and productivity with evidence supported by a production function. The differences in Piedmont (e.g., ownership size, market access, terrain, population density, etc.) may combine to limit daily production and labor productivity.
volume: 44, issue:
Log truck gross vehicle weight (GVW) limits in the US state of Georgia are among the lowest of any timber-producing state in the US and are far below GVW limits in countries such as Australia, Canada, Finland, and Sweden. In the state of Georgia, log trucks travel on county and state roads between harvest sites and forest industry mills. Most county roads were not constructed to support heavy trucks and so log trucks may damage these roads, even at the low GVW limits allowed in Georgia. Local governments sometimes enact timber harvesting ordinances to constrain timber transportation and often oppose efforts to increase GVW limits. The purpose of this study was to document local transportation officials’ perceptions of timber harvesting and transportation and to measure their support or opposition to alternative log truck weights and configurations. A telephone survey of county transportation superintendents or their equivalent was conducted in Georgia during the summer of 2020. Forty-three county officials responded to the survey, yielding a response rate of 43%. Ninety-eight percent of respondents reported that timber harvesting was important to their local economy, and 86% agreed that local governments were cooperative with log truck owners. County officials were concerned about damage from overweight log trucks and mud on public roads. The average preferred GVW and tandem axle weight limits were approximately 10% lower than the existing limits. County officials opposed six- and seven-axle 45,359 kg (100,000 lbs) GVW configurations but did support allowing log trucks to operate on interstate highways at current state weight limits. Findings suggest that logging businesses and mills should focus on improving compliance with weight laws, improving the condition of log trucks, and maintaining or improving relationships with the public and local government officials.
volume: 44, issue:
The demand for increased efficiency in timber harvesting has traditionally been met by continuous technical improvements in machines and an increase in mechanisation. The use of active and passive sensors on machines enables improvements in aspects such as operational efficiency, fuel consumption and worker safety. Timber harvesting machine manufacturers have used these technologies to improve the maintenance and control of their machines, to select and optimise harvesting techniques and fuel consumption. To a more limited extent, it has also been used to evaluate the time taken to complete tasks. The systematic use of machine sensor data, in a central database or cloud solution is a more recent trend.
Machine data is recorded over long periods of time and at high resolution. This data therefore has considerable potential for scientific investigations. For mechanised timber harvesting operations, this could include a better understanding of the interaction between productivity and operational parameters, which first of all requires an efficient determination of cycle time.
This study was the first to automatically delimitate tower yarder cycle times from machine sensor data. In addition to machine sensor data, cycle times were collected through a traditional manual time and motion study, and cycle times from both studies were compared to a reference cycle time determined from video footage of the yarder in operation.
Based on three days of detailed time study, the total cycle time in the classic manual time (–1.3%) and in the machine sensor data (–1.2%) was only slightly shorter than in the reference study, and the average cycle time did not differ significantly (classic manual time study: –0.08±0.94 min, p=0.997; machine sensor data study: –0.08±0.26 min, p=0.997). However, the accuracy of the machine sensor approach (RMSE=0.92) was more than three times higher than that of the classic manual time study (RMSE=0.27).
With the integration of sensors on forestry machines now being commonplace, this study shows that machine sensor data can be reliably interpreted for time study purposes such as machine or system optimisation. This eliminates the need for manual time study, which can be both cumbersome and dependent on the experience of the observer, and allows long term data sets to be obtained and analysed with comparatively little effort. However, a truly automated time study needs to be supplemented with automated determination of and linkage to other operational parameters, such as yarding and lateral yarding distance or load volume.
volume: 45, issue:
The aim of the study was to provide a comprehensive overview of global long-distance road transportation of industrial roundwood. The study focused on the maximum gross vehicle weight (GVW) limits allowed with different timber truck configurations, typical payloads in timber trucking, the road transportation share of the total industrial roundwood long-distance transportation volume, and the average long-distance transportation distances and costs of industrial roundwood. The study was carried out as a questionnaire survey. The questionnaire was sent to timber transportation logistics experts and research scientists in the 30 countries with the largest industrial roundwood removals in Europe, as well as selected major forestry countries in the world (Argentina, Australia, Brazil, Canada, Chile, China, Japan, New Zealand, South Africa, Türkiye, the United States of America and Uruguay) in February 2022, and closed in May 2022. A total of 31 countries took part in the survey. The survey illustrated that timber trucking was the main long-distance transportation method of industrial roundwood in almost every country surveyed. Road transportation averaged 89% of the total industrial roundwood long-distance transportation volume. Timber truck configurations of 4 to 9 axles with GVW limits of around 30 tonnes to over 70 tonnes were most commonly used. The results indicated that higher GVW limits allowed significantly higher payloads in timber trucking, with the lowest payloads at less than 25 tonnes, and the highest payloads more than 45 tonnes. The average road transportation distance with industrial roundwood was 128 km, and the average long-distance transportation cost in timber trucking was €11.1 per tonne of timber transported. In the entire survey material, there was a direct relationship between transportation distance and transportation costs and an inverse relationship between maximum GVW limits and transportation costs. Consequently, in order to reduce transportation costs, it is essential to maximise payloads (within legal limits) and minimise haul distances. Several measures to increase cost- and energy-efficiency, and to reduce greenhouse gas emissions in road transportation logistics, are discussed in the paper. On the basis of the survey, it is recommended that up-to-date statistical data and novel research studies on the long-distance transportation of industrial roundwood be conducted in some countries in the future.
volume: 45, issue:
Labour force represents the sum of human physical and mental abilities used for the production of whatever kind of use values. In forestry, the performance of work operations, especially wood harvesting, represents a high-risk, physically intensive, and professionally very demanding activity, which inevitably requires a qualified and sustainable labour force. Professional, skilful and motivated forestry workers are the basic requirement for efficient forestry operations and make a constituent part of todays sustainable forest management. However, the forestry sector has recently been facing the increasing problem of a shortage of forestry workers i.e. the major challenge of obtaining the necessary labour force. The reasons for this are different demographic, economic, technological and political processes, as well as the specifics of the forestry sector itself. Therefore, in addition to some general indicators of the forestry workforce condition in Europe and worldwide, this paper presents forestry experts’ reflections on the future perspectives of forest work in Bosnia and Herzegovina. Special attention is paid to current issues and problems in attaining and ensuring the necessary labour force (attitudes on forestry work and the profession of forestry worker, gravity of the labour shortage, leading causes and reasons for the lack of forestry workers) and to possible measures and instruments important for improving the forestry workforce sustainability (factors for successful recruitment of forestry workers, stronger retention of workers, greater work commitment, general forest management issues affecting workforce sustainability, etc.). The opinions of forestry experts in public and private companies were statistically tested for differences. The aim of the study is to sensibilize the sector and the public on the problems of the labour force in forestry, its condition and status, and to create the basis that can contribute to bettering the status and sustainability of the labour force in forestry.
volume: 45, issue:
A dynamic programing algorithm to identify schedules that minimize the discounted cost (DC) of logging machines over a planning horizon including gains from technological progress was used. The identified schedules were also compared with three alternative replacement policies derived from the literature and Brazilian forestry companies. The case study used a harvester and a forwarder and a 100-year planning horizon, where the maximum replacement limit was 8 years. To apply the dynamic programing algorithm, it was necessary to generate lists from cash flows, which incorporated the possible replacement combinations of a series of machines according to the length of the planning horizon and the maximum replacement limit. The lists were formed by three descriptors: predecessor node (moment of purchase of the machine), future node (point of sale for the acquisition of a new machine), and arc value (DC information, the mean production cost and mean production). The results show that the DC identified for the series of harvester replacements was higher compared to the forwarder. It was also identified that the harvester's economic life is shorter, and with technological progress, there was a reduction in the economic life of both machines. Technological progress was also responsible for reducing the average production cost and increasing the average production of machines. When comparing the alternative schedules (AS), it was found that, although AS had a higher DC value and mean production costs, there was very little difference between them. In the harvester's case, AS01 had the highest DC value ($4.36 million). By choosing it, the decision maker would bear a DC boost of $54,000, while AS02 and AS03 would trigger an increase of $43,000 and $32,000, respectively. For the forwarder, the schedule with the highest DC value was AS03 ($3.69 million). The postponement of the replacements made in alternative schedule 01 and alternative schedule 02 resulted in an increase in the DC of $5000, while the anticipation of the replacements made in the alternative schedule 03 resulted in an increase of $48,000. The aspect that stood out the most, in relation to the results presented, was the small variation that the alternative schedules presented in relation to the schedules obtained using the dynamic programing algorithm. With a DC variation of less than 1.4%, the results lead us to conclude that the decision maker will not suffer much harm in choosing any of the alternative schedules tested.
volume: 45, issue: 2
The Technodiversity project addresses technological diversity by gathering a common basis of technological knowledge and increasing the sensitivity for diversity in forest engineering. It aims to bring together and make generally available the existing knowledge in forest operations that is scattered across various European countries. It will serve as a bridge between different regions of Europe and generations of students, practitioners, scientists and academics. In this article, a small part of the e-learning module (https://technodiversity-moodle.ibe.cnr.it/) is presented in a glossary of some of the terms of forest operations.
volume: 45, issue: 2
Climate crises and natural disasters increasingly challenge wood supply chains by the critical need to transport high volumes of salvage wood quickly out of the forests to limit wood value loss and to prevent inducing forest calamities. Salvage wood logistics covering unimodal, multimodal and multi-echelon unimodal transport as well as storage plays an essential role in tackling existing problems and future risks by linking diverse actors along wood supply chains. Since little is known about specific challenges in salvage wood logistics, an extensive empirical study was conducted to evaluate logistics concepts and coping strategies involving stakeholders representing the entire wood value chain in Austria. The knowledge and experience of 161 forest owners, transport operators and wood-based industry actors were surveyed based on questionnaires with 108 matrix, rating, Likert scale and open questions. Results show a significant loss in salvage wood transport capacity due to long waiting times at receiving mills leading to more than one-fourth lost transport capacity in the unimodal salvage wood supply chain. Sustainable and resilient wood supply chain management can be achieved by increasing train and semitrailer truck wood transport as well as wood storage capacity and by improving both working conditions for self-loading log-truck drivers and cooperation between stakeholders.
volume: 46, issue: 1
Forwarders often load logs organized in large piles by modified farm tractors, skidders, animals, other forwarders, etc., but currently, there are no studies on how the different concentrations of logs affect forwarder performance in terms of time consumption, productivity, and costs in forwarding operations. A study was conducted in three locations situated in Bulgaria (sites A and B) and in southern Italy (site C): in site A the logs were spread in the stand, in site B they were concentrated in large piles at the roadside, whereas in site C the logs were organized at the roadside in piles of medium size. The average forwarder productivity in site A obtained at an average forwarding distance of 1780 m, an average payload volume of 9.83 m3, and an average number of grips of logs with the crane grapple, during loading (22.97) and during unloading (8.97) per cycle, is 10.43 m3·PMH-1 (PMH, productive machine hour) and 9.93 m3·SMH-1 (SMH, scheduled machine hour), respectively. In site B the productivity rate was lower than that registered by the forwarder operated in site A: 9.38 m3·PMH-1 and 8.81 m3·SMH-1, respectively, at an average forwarding distance of 3760 m, average payload volume of 15.04 m3, and a mean number of grips of logs with the crane grapple, during loading and during unloading, of 23.57 and 14.10 per cycle, respectively. With regard to site C, the average machine productivitiy was 12.39 m3·PMH-1 and 11.85 m3·SMH-1, travelling a mean forwarding distance of 1630 m, transporting a mean load volume of 13.63 m3, and performing an average number of grips of logs with the crane grapple, during loading of 26.52 and during unloading of 12.36 per cycle. The ratio between the number of grips of logs with the crane grapple during loading and unloading operations in site A is on average 2.56, but in site B it is significantly smaller – mean of 1.67, due to the larger number of logs in the grapple when loading from large piles. Site C shows a loading and unloading number of grips ratio intermediate between the two Bulgarian sites. This ratio is characterized by the concentration of logs in the stand. Concentration in larger piles results in a larger volume of grappled logs by crane, and hence, lower time for loading of the forwarder and higher productivity. The obtained results show that the dispersion of small piles of logs results in a smaller volume grappled, a greater number of crane cycles and a larger loading distance, which generally, increases loading time. The larger volume of logs in the crane grapple and the shorter loading distance, when the loading operation is carried out from larger piles at the roadside, lead to less loading time. Gross costs for forwarders were 65.14 € PMH-1 at Site A, 72.96 €·PMH-1 at Site B, and 85.58 €·PMH-1 at Site C. When the forwarders were productive, the costs were 6.35 €·m-3 in site A, 7.90 €·m-3 in site B, and 6.90 €·m-3 in site C.
volume: issue, issue:
Forwarders often load logs organized in large piles by modified farm tractors, skidders, animals, other forwarders, etc., but currently, there are no studies on how the different concentrations of logs affect forwarder performance in terms of time consumption, productivity, and costs in forwarding operations. A study was conducted in three locations situated in Bulgaria (sites A and B) and in southern Italy (site C): in site A the logs were spread in the stand, in site B they were concentrated in large piles at the roadside, whereas in site C the logs were organized at the roadside in piles of medium size. The average forwarder productivity in site A obtained at an average forwarding distance of 1780 m, an average payload volume of 9.83 m3, and an average number of grips of logs with the crane grapple, during loading (22.97) and during unloading (8.97) per cycle, is 10.43 m3·PMH-1 (PMH, productive machine hour) and 9.93 m3·SMH-1 (SMH, scheduled machine hour), respectively. In site B the productivity rate was lower than that registered by the forwarder operated in site A: 9.38 m3·PMH-1 and 8.81 m3·SMH-1, respectively, at an average forwarding distance of 3760 m, average payload volume of 15.04 m3, and a mean number of grips of logs with the crane grapple, during loading and during unloading, of 23.57 and 14.10 per cycle, respectively. With regard to site C, the average machine productivitiy was 12.39 m3·PMH-1 and 11.85 m3·SMH-1, travelling a mean forwarding distance of 1630 m, transporting a mean load volume of 13.63 m3, and performing an average number of grips of logs with the crane grapple, during loading of 26.52 and during unloading of 12.36 per cycle. The ratio between the number of grips of logs with the crane grapple during loading and unloading operations in site A is on average 2.56, but in site B it is significantly smaller – mean of 1.67, due to the larger number of logs in the grapple when loading from large piles. Site C shows a loading and unloading number of grips ratio intermediate between the two Bulgarian sites. This ratio is characterized by the concentration of logs in the stand. Concentration in larger piles results in a larger volume of grappled logs by crane, and hence, lower time for loading of the forwarder and higher productivity. The obtained results show that the dispersion of small piles of logs results in a smaller volume grappled, a greater number of crane cycles and a larger loading distance, which generally, increases loading time. The larger volume of logs in the crane grapple and the shorter loading distance, when the loading operation is carried out from larger piles at the roadside, lead to less loading time. Gross costs for forwarders were 65.14 € PMH-1 at Site A, 72.96 €·PMH-1 at Site B, and 85.58 €·PMH-1 at Site C. When the forwarders were productive, the costs were 6.35 €·m-3 in site A, 7.90 €·m-3 in site B, and 6.90 €·m-3 in site C.
volume: issue, issue:
Today in many countries and regions, forestry sector deals with a considerable shortage of forestry workers and faces the serious challenge of ensuring a qualified and sustainable workforce. Current global processes and structural changes, such as emigration from rural areas, aging of the population, unfavorable age structure of existing employees, negative demographic trends (migrations, decline in birth rate, negative natural increase, etc.), lack of interest in the so-called 3D (dirty, dangerous and demeaning) jobs, low cost of labor and others, significantly contribute to such an adverse situation. Additionally, forestry work, especially wood harvesting, represents a very risky, professionally highly demanding and physically extremely intensive activity, which is regularly classified as one of the most dangerous occupations with a high proportion of serious injuries, fatalities and occupational diseases. For these reasons, the forestry profession is considered unattractive, and the job of a forestry worker undesirable. All of this makes finding the people interested in these jobs very difficult, and the task of ensuring the necessary workforce for all regular activities in sustainable forest management becomes very hard. In this paper, based on the surveys carried out in the Federation of Bosnia and Herzegovina (FB&H), i.e. evaluation of forestry workforce sustainability factors, and on the study of available strategic documents, policies and case studies, strategic directions aimed at strengthening the sustainability of forestry workforce were elaborated. The sustainability factors were observed in three categories related to: a) stronger recruiting in forestry, b) more successful retention of forestry workers, and c) higher work commitment of forestry workers. Established rankings, together with other findings, were used to define four separate strategic directions: (1) Direct financial strategy, which emphasizes direct monetary payments to workers and is oriented towards labor productivity, (2) Indirect financial strategy, which focuses more on providing indirect material gains to workers and the quality of performed work, (3) Educational strategy, aimed at the education and training of workers, and (4) Technical-technological strategy, aimed at increasing the mechanization in forest operations thus reducing the demand for labor. The paper elaborates the basic starting points and main characteristics (priorities, measures and activities, stakeholders, responsible authorities, etc.) of each strategic direction considering the possibility and conditions of their implementation in national forestry sector. The objective of the paper is to raise the required awareness of the forestry workforce issues, its position and status, and also to provide foundations for enhancing the attractiveness of forestry work and improving the overall sustainability of the forestry workforce. The results of the study point out the critical issues and provide valuable insights that can help in formulating effective policies and strategies for the future.
volume: 46, issue: 1
Today in many countries and regions, forestry sector deals with a considerable shortage of forestry workers and faces the serious challenge of ensuring a qualified and sustainable workforce. Current global processes and structural changes, such as emigration from rural areas, aging of the population, unfavorable age structure of existing employees, negative demographic trends (migrations, decline in birth rate, negative natural increase, etc.), lack of interest in the so-called 3D (dirty, dangerous and demeaning) jobs, low cost of labor and others, significantly contribute to such an adverse situation. Additionally, forestry work, especially wood harvesting, represents a very risky, professionally highly demanding and physically extremely intensive activity, which is regularly classified as one of the most dangerous occupations with a high proportion of serious injuries, fatalities and occupational diseases. For these reasons, the forestry profession is considered unattractive, and the job of a forestry worker undesirable. All of this makes finding the people interested in these jobs very difficult, and the task of ensuring the necessary workforce for all regular activities in sustainable forest management becomes very hard. In this paper, based on the surveys carried out in the Federation of Bosnia and Herzegovina (FB&H), i.e. evaluation of forestry workforce sustainability factors, and on the study of available strategic documents, policies and case studies, strategic directions aimed at strengthening the sustainability of forestry workforce were elaborated. The sustainability factors were observed in three categories related to: a) stronger recruiting in forestry, b) more successful retention of forestry workers, and c) higher work commitment of forestry workers. Established rankings, together with other findings, were used to define four separate strategic directions: (1) Direct financial strategy, which emphasizes direct monetary payments to workers and is oriented towards labor productivity, (2) Indirect financial strategy, which focuses more on providing indirect material gains to workers and the quality of performed work, (3) Educational strategy, aimed at the education and training of workers, and (4) Technical-technological strategy, aimed at increasing the mechanization in forest operations thus reducing the demand for labor. The paper elaborates the basic starting points and main characteristics (priorities, measures and activities, stakeholders, responsible authorities, etc.) of each strategic direction considering the possibility and conditions of their implementation in national forestry sector. The objective of the paper is to raise the required awareness of the forestry workforce issues, its position and status, and also to provide foundations for enhancing the attractiveness of forestry work and improving the overall sustainability of the forestry workforce. The results of the study point out the critical issues and provide valuable insights that can help in formulating effective policies and strategies for the future.
volume: issue, issue:
Quadratic mean diameter is a widely used stand parameter present in the stand inventory summaries, while the top stand diameter is rarely reported in the literature, mainly in relation to dominant stand height. Since the dominant stand height is usually determined from the tree height-diameter curve of the stand, it is important how the top tree assemblage, used to estimate dominant diameter, is defined. The main objective of our study was to assess the bias between differently defined dominant diameter estimates for monospecific plantations of various species, to model the dominant diameter as a function of quadratic mean diameter and other relevant stand variables, and to estimate its goodness-of-fit in predicting dominant diameter and dominant height.
We used data records gathered in sample plots in monospecific plantations of four tree species: Scots pine, Black pine, black locust and hybrid black poplar. We calculated the quadratic and arithmetic mean diameters of the 20% thickest trees in the plots, and the quadratic and arithmetic mean diameters of the trees, whose number corresponded to the 100 thickest trees per hectare. For each dataset, we analyzed the range and the distribution of the relative deviations calculated for each pair of dominant diameter estimates. For the Black pine plantations, regression models were developed for the two dominant diameter definitions, whose values differed most. Their goodness-of-fit was assessed from model efficiency and error statistics. The same model derivation procedure, applied to the Scots pine data, was followed by substitution of the predicted dominant diameter into a height-diameter model to assess the goodness-of-fit of the dominant height predictions.
The differences between the arithmetic and quadratic means, estimated from the same subsample of trees, did not exceed 2% in all cases. However, dominant stand diameters calculated as averages of differently defined largest tree collectives differed by as much as 35%. Regardless of its definition, the dominant stand diameter was adequately predicted by a function of the quadratic mean diameter alone or considering stand basal area as a second predictor. The models showed very good accuracy of model efficiency above 0.92, average absolute error below 8%, with 90% of the relative errors less than 15%. The predicted dominant diameter value can be used in a height-diameter model to estimate with confidence the dominant stand height of a monospecific forest plantation, allowing the forecast of the stand attributes based on dominant trees when only average stand variables are known.