Volume 43 No.1
Current issues:Volume 43 No.1Latest papersMore

Volume 43 No.1

Fuel Consumption, Greenhouse Gas Emissions, and Energy Efficiency of Wood-Harvesting Operations: A Case Study of Stora Enso in Finland

volume: 43, issue:

The EU’s climate and energy framework and Energy Efficiency Directive drive European companies to improve their energy efficiency. In Finland, the aim is to achieve carbon neutrality by 2035. Stora Enso Wood Supply Finland (WSF) had a target, by 2020, to improve its energy efficiency by 4% from the 2015 level. This case study researches the use of the forest machine fleet contracted to Stora Enso WSF. The aims were to 1) clarify the forest machine fleet energy-efficiency as related to the engine power; 2) determine the fuel consumption and greenhouse gas (GHG) emissions from wood-harvesting operations, including relocations of forest machines by trucks; and 3) investigate the energy efficiency of wood-harvesting operations. The study data consisted of Stora Enso WSF’s industrial roundwood harvest of 8.9 million m3 (solid over bark) in 2016. The results illustrated that forest machinery was not allocated to the different cutting methods (thinning or final felling) based on the engine power. The calculated fuel consumption totalled 14.2 million litres (ML) for harvesting 8.9 million m3, and the calculated fuel consumption of relocations totalled 1.2 ML, for a total of 15.4 ML. The share of fuel consumption was 52.5% for harvesters (cutting), 39.5% for forwarders (forest haulage), and 8.0% for forest machine relocations. The average calculated cubic-based fuel consumption of wood harvesting was 1.6 L/m3, ranging from the lowest of 1.2 L/m3 for final fellings to the highest of 2.8 L/m3 in first thinnings. The calculated fuel consumption from machine relocations was, on average, 0.13 L/m3. The calculated carbon dioxide equivalent (CO2 eq.) emissions totalled 40,872 tonnes (t), of which 21,676 t were from cutting, 16,295 t were from forwarding, and 2,901 t from relocation trucks. By cutting method, the highest calculated CO2 eq. emissions were recorded in first thinnings (7340 g CO2 eq./m3) and the lowest in final fellings (3140 g CO2 eq./m3). The calculated CO2 eq. emissions in the forest machine relocations averaged 325 g CO2 eq./m3. The results underlined that there is a remarkable gap between the actual and optimal allocation of forest machine fleets. Minimizing the gap could result in higher work productivity, lower fuel consumption and GHG emissions, and higher energy efficiency in wood-harvesting operations in the future.

Evaluation of Fuel Quality, Throughput Rate and Energy Consumption During Non-Industrial Wood Chip Production with Three PTO Driven Chippers

volume: 43, issue:

Physical wood chip quality is essential for failure-free and low emission combustion in small-scale boilers ≤100 kW. In Bavaria, these furnaces are often operated by farmers or private forest owners that produce their own fuels using small to medium sized PTO-driven chippers. As secondary fuel processing steps such as industrial screening are usually too expensive for private forest owners, the selection of suitable raw materials and process parameters to directly produce high quality fuels during chipping are deemed especially relevant for this user group. In the present study, three commonly used small-scale chippers ≤150 kW, i. e. a drum, a spiral and a disc chipper where evaluated in terms of fuel quality, throughput rate and energy consumption during wood chip production. Chipping was done using stem wood of European beech and Norway spruce. Machine settings were the ones recommended by the chipper manufactures for the production of high quality fuels. Additional chipping variants included the use of different raw materials such as crown residues of European willow and varying machine settings including blunt knives, increasing spiral cut length, large screen mesh sizes or increased PTO speeds. Representive wood chip samples were taken after each trial and analysed in their physical fuel properties according to international standards for solid biofuels but also using a continuously measuring image analysis device to determine particle length and particle shape. For all three mobile chippers, wood chips with the particle size class »P31s« according to the revised ISO 17225-4:2021 could be produced when stem wood was used as assortment. Fine content of chips, i. e. particles ≤3.15 mm, was lowest for the spiral chipper and increased for the drum and disc chipper, especially when blunt knives or narrow screen meshes were used for chipping. At the same time, blunt knives increased the particle shape factor (PSF) of the bulk materials indicating a rather broken particle surface structure compared to clean cut particles. Throughput rate decreased and energy consumption increased when fuels with small particle size were produced, e. g. when narrow screen meshes or narrow chipping spirals were applied. This trend was particularly pronounced when blunt knives were used for chipping due to grinding of the material. All three chippers could be recommended for the production of high quality fuels for small-scale boilers when suitable machine settings and raw materials are applied for chipping.

Business Process Reengineering of a Large-Scale Public Forest Enterprise Through Harvester Data Integration

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.

Essential Issues Related to Construction Phases of Road Networks in Protected Areas: A Review

volume: 43, issue:

Protected areas play an active role in protecting natural resources and wildlife habitat. These areas must be accessible within protection-use balance. For this reason, road networks in protected areas are one of the main functions of sustainable infrastructure services. The construction phases of road networks in these sensitive areas should be considered in planning within the balance of protection-use with interdisciplinary studies. Especially during the construction of the road network, it is necessary to pay attention to the construction machinery used, geotextile materials, hydraulic and ecological road structures, plantation of the slopes, fences that increase the visual quality and work schedule. Based on a related literature survey, the issues to be considered during the construction phases of road networks (i.e. road planning, tree felling and removing, excavation and embankment, subgrade finishing, road structures and surfacing) in protected areas were evaluated under nine headings. The implementation phases of these issues are important in reducing the adverse effects that will occur in protected areas. In this regard, during the construction phases of road networks, the issues to be considered were evaluated together with the conceptual indicators in terms of management, technique, economy, ecology, and aesthetics. Matters needing attention according to the sensitivity of conceptual indicators during the construction phases of road networks in and around protected areas that contain sensitive ecosystems have been identified and presented in a framework to further the discussions on this issue. Accordingly, the use of the issues to be considered in the planning and construction of road networks with conceptual indicators will help evaluate the planning phase before and after construction. In particular, it can be expected to lead to the creation of a checklist after the planning phase. Thus, the continuity of the issues to be considered during the maintenance, repair, and construction phases of the new road networks or existing road networks planned to be built in a protected area and surrounding areas will provide significant contributions to the functions of the protected areas. The main contributions may include increasing the number of visitors to the protected areas, reducing impacts on wildlife in protected areas by implementing innovative technologies, and developing alternative modes in tourism industry.

Field Setup and Assessment of a Cloud-Data Based Crane Scale (CCS) Considering Weight- and Local Green Wood Density-Related Volume References

volume: 43, issue:

When investigating the forwarding process within the timber supply chain, insufficient data often inhibits long-term studies or make real-time optimisation of the logistics process difficult. Information sources to compensate for this lack of data either depend on other processing steps or they need additional, costly hardware, such as conventional crane scales. An innovative weight-detection concept using information provided by a commonly available hydraulic pressure sensor may make the introduction of a low-cost weight information system possible. In this system, load weight is estimated by an artificial neural network (ANN) based on machine data such as the hydraulic pressure of the inner boom cylinder and the grapple position.

In our study, this type of crane scale was set up and tested under real working conditions, implemented as a cloud application. The weight scale ANN algorithm was therefore modified for robustness and executed on data collected with a commonly available telematics module. To evaluate the system, also with regard to larger sample sizes, both direct weight-reference measurements and additional volume-reference measurements were made. For the second, locally valid weight-volume conversion factors for mainly Norway spruce (Picea abies, 906 kg m-3, standard error of means (SEM) of 13.6 kg m-3), including mean density change over the observation time (–0.16% per day), were determined and used as supportive weight-to-volume conversion factor.

Although the accuracy of the weight scale was lower than in previous laboratory tests, the system showed acceptable error behaviour for different observation purposes. The twice-observed SEM of 1.5% for the single loading movements (n=95, root-mean-square error (RMSE) of 15.3% for direct weight reference; n=440, RMSE=33.2% for volume reference) enables long-term observations considering the average value, but the high RMSE reveals problems with regard to the single value information.

The full forwarder load accuracy, as unit of interest, was observed with an RMSE of 10.6% (n=41), considering a calculated weight-volume conversion as reference value. An SEM of 5.1% for already five observations with direct weight reference provides a good starting point for work-progress observation support.

Evaluating the Accuracy of Remote Dendrometers in Tree Diameter Measurements at Breast Height

volume: 43, issue:

An accurate tree diameter (DBH) measurement is a significant component of forest inventory. This study assessed the reliability of remote dendrometers to measure tree DBH. We compared direct caliper measurements (reference measurements) to the remote measurements collected from a laser caliper and a smartphone at 0.5 m, 1 m, and 1.5 m distances from each tree within three forest types (pine, oak, and poplar forests). In general, all remote dendrometers underestimated the mean diameter compared to direct caliper measurements, regardless of forest types and distances. We observed that the mean deviation of direct caliper measurement and smartphone measurement at 1.5 m within a pine forest and oak forest were the lowest (0.3 cm and 0.36 cm, respectively). The deviations between direct caliper measurements and smartphone measurements at a 0.5 m distance, across forest types, were noticeably larger compared to others. An ANOVA test was used to determine whether significant deviations existed between caliper measurements and remote measurements at a specific distance, and among three different forest types. We rejected the null hypothesis, which suggested that there were no statistically significant differences (p<0.05) between tree DBH measurements obtained from the direct caliper measurements and indirect measurements (smartphone and laser caliper) captured at a distance. Then, a post-hoc test was performed to examine which set of estimated deviations was different from the reference data. The results suggested that indirect tree DBH measurements using the smartphone app at 1 m and 1.5 m in certain forest types (pine and oak) were not significantly different from direct tree DBH measurements. Also, our test results mostly indicated no significant difference within each forest, except for measurements using the smartphone app at 0.5 m across all forest types when the smartphone measurements were compared to laser caliper measurements. Although forest characteristics and measurement distance may play an important role in remote tree DBH measurement accuracy, the smartphone app may be used as a practical alternative to direct measurement in measuring the DBH of a tree, which may be a positive development for forestry due to the increased use of smartphones and the availability of a free measure app.

ESPDS: A Support Tool to Assist Forest Equipment Purchase Decisions

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:

Assessment of Chainsaw Operators Training in Andalusia (Spain)

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.

Influence of Intelligent Boom Control in Forwarders on Performance of Operators

volume: 43, issue:

This paper deals with the influence of an Intelligent Boom Control (IBC) in forwarders on the work of operators. The work with the IBC and standard system of crane control was measured by the use of a John Deere harvester and forwarder simulator. Two individuals without any practical training and two individuals with experience in the control of the crane took the measurements. The monitoring included eight different performance indicators. The use of the IBC system allowed the untrained operators to increase their work output by 27. With the use of the IBC system, these individuals also showed 53% fewer direct damages to the machine. However, our findings show that the length of experience influenced the performance of the operators out of all the monitored indicators. Notwithstanding that fact, the use of the IBC system has a direct positive influence on the economy of the machine operation.

Determining Harvester Productivity Curves of Thinning Operations in Birch Stands of Central Europe

volume: 43, issue:

Silver birch (Betula pendula Roth) is a popular tree species forming stands in nearly the whole of Europe. In Poland, birch is one of the most representative broadleaved species growing on rather poor soils, very often as a mix species with Scots pine (Pinus sylvestris L.). In Central Europe, birch forms trunk often with sweeps, and at the older age with thick branches. Due to that, a harvester thinning operation in birch stands can be challengeable when trying to process logs from the top part of trees, which can finally impact on productivity. The objective of this research was to determine harvester productivity for birch with particular attention to production of logs from the top part of a tree. The research was carried out in stands of North and North-West Poland. All together 21 tests were completed in 16 stands, in which 9 harvesters were used (8 different models). The mean diameter of harvested trees was 23.7 cm with the mean height of 21.7 m. Obtained productivity without delays was on average 21.98 m3 h-1 and varied from as low as 5.14 to maximum 44.66 m3 h-1, and depended mainly on harvested tree size. It was also confirmed that top diameter of the last log depended on diameter at breast height (DBH). The model developed based on that relationship can be used for prediction of biomass volume from birch stands when harvesters are used for thinning.

Potential Evaluation of Forest Road Trench Failure in a Mountainous Forest, Northern Iran

volume: 43, issue:

After road construction in steep and mountainous areas, there is always a risk for trench failure. Estimation of this probability before forest road design and construction is urgent. Besides, to decrease failures costs and risks, it is necessary to classify their occurrence probabilities and identify the factors affecting them. The present study compares three statistical models of logistic regression, frequency ratio, and maximum entropy. The robust one was applied to generate trench failures susceptibility map of forest roads of two watersheds in Northern Iran. Also, all failures repairing costs were estimated, and subsequently, all existing roads were surveyed in the study area, detecting 844 failures. Among the recorded failures, 591 random cases (70%) were used in modeling, and others (30%) were used as validation data. The digital layers, including failure locations, were prepared. Three failure susceptibility maps were simulated using the outputs of the mentioned methods in the GIS environment. The resulted maps combined with repair cost prices were analyzed to statistically evaluate the repair cost unit per meter of forest road and per square meter of failure. The results showed that the logistic regression model had an Area Under Curve (AUC) of 74.6% in identifying failure-sensitive areas. The probabilistic frequency ratio and Entropy models showed 68.2 and 65.5% accuracy, respectively. Based on the logistic regression model, the distance to faults and terrain slope factors had the highest effects on forest road trenches failures. According to the result, about 43.25% of the existing road network is located in »high« and »very high« risky areas. The estimated cost of regulating and profiling trenches and ditches along the existing roads was approximately 108,772 $/km.

Cutlink Cleaning Head with a Spreading Feature for Biological Sprout Control

volume: 43, issue:

The ability of deciduous trees to sprout efficiently after cutting is problematic in young forests where the target is to cultivate coniferous trees for industry. Since the use of chemicals has been restricted, new alternatives are needed. One potential and environmentally friendly option is biological sprout control that is based on the use of a white-rot fungus, Chondrostereum purpureum (Pers. Ex Fr.) Pouzar. This method has been efficient in earlier investigations when performed manually, but efficient, fully mechanized devices which are able to cut and treat stumps with a fungus are still unavailable. Therefore, the efficacy of biological sprout control conducted with a Cutlink cleaning head equipped with a spreading feature was studied in two young Norway spruce (Picea abies (L.) H. Karst.) forests in central Finland.

Sample plots for the control (cutting deciduous saplings only) and fungal treatment (cutting and spreading fungal inoculum on fresh stump surfaces) were established, and the ability of the Cutlink cleaning head in preventing sprouting of silver and downy birch (Betula pendula Roth and B. pubescens Ehrh., respectively) in the sample plots was investigated for two years.

In the near vicinity of cultivated Norway spruce, the proportion of cut deciduous saplings varied from 50–60% after the Cutlink operation. The average mortality of silver and downy birch stumps in the fungal treatment plots was ca. 40%, while stump mortality in the control, i.e., cutting only, was only ca. 13%, after two years. Stump mortality increased up to 73% if the stumps did not include old branches, i.e., the stump was cut to a low enough height.

These results confirmed that the Cutlink cleaning head is a potential tool in young stand management operation but further development will be needed in working methods in order to achieve lower stump heights (no branches on the stump) and also to increase the proportion of cut saplings.

Forest Fire Risk Zone Mapping of Eravikulam National Park in India: A Comparison Between Frequency Ratio and Analytic Hierarchy Process Methods

volume: 43, issue:

Forest fire is one of the most common natural hazards occurring in the Western Ghats region of Kerala and is one of the reasons for forest degradation. This natural disaster causes considerable damage to the biodiversity of this region during the dry fire season. The area selected for the present study, Eravikulam National Park, which is predominantly of grassland vegetation, is also prone to forest fires. This study aims to delineate the forest fire risk zones in Eravikulam National Park using remote sensing (RS) data and geographic information system (GIS) techniques. In the present study, methods such as Analytic Hierarchy Process (AHP) and Frequency Ratio (FR) were used to derive the weights, and the results were compared. We have used seven factors, i.e. land cover types, normalized difference vegetation index, normalized difference water index, slope angle, slope aspect, distance from the settlement, and distance from the road to prepare the fire risk zone map. The area of the prepared risk zone maps is divided into three zones, namely low, moderate, and high. From the study, it was found that the fire occurring in this area is due to natural as well as anthropogenic factors. The prepared forest fire risk zone maps are validated using the fire incidence data for the period from January 2003 to June 2019 collected from the records of the Forest Survey of India. The investigation revealed that 72% and 24% of the fire incidences occurred in the high risk zone of the maps prepared using the AHP and FR methods, respectively, which ascertained the superiority of the AHP method over the FR method for forest fire risk zone mapping. The receiver operating characteristic (ROC) curve analysis gives an area under the ROC curve (AUC) value of 0.767 and 0.567 for the AHP and FR methods, respectively. The risk zone maps will be useful for staff of the forest department, planners, and officials of the disaster management department to take effective preventive and mitigation measures.

Introducing a New Approach in Stand Tending Planning and Thinning Block Designation by Using Mixed Integer Goal Programming

volume: 43, issue:

Long-term management plans have been developed for nearly all of the forests in Turkey. These plans are applied at a sub-district management unit level and may contain guidance for both intermediate yield and final yield harvests. To implement an intermediate yield plan, which involves the scheduling of forest thinnings (stand tending), consideration in Turkey is given to the advantages of working in the same terrain and the same general area each year. Therefore, compartments are often clumped together to create thinning blocks, taking into consideration the thinning priority of the stands, road conditions, site index, age, and proximity of the compartments. Further, when preparing annual budgets and planning to meet the market’s needs, forest enterprises require an even flow of intermediate wood volume each year. In this paper, we introduce a new approach in stand tending planning designed to schedule an equal amount of intermediate wood volume each year and to create thinning blocks by minimizing the distance to pre-defined ramps (landings). We developed both linear and nonlinear goal programming models to minimize both the deviations from a harvest volume (annual intermediate yield allowable cut) target and the deviations from a target value determined for the distances (total and average) of the centroid of each compartment to the hypothetical forest ramps. By using the extended version of Lingo 16, we solved the problem with different weights for the deviations in volume and distance that ranged from 0.0 to 1.0, in 10% intervals, which created 11 scenarios. We carefully analyzed the results of each scenario by taking into consideration the wood volume and distance of compartments to the ramps. The best scenario using the linear model produced a deviation in volume scheduled for the entire decade of 6 m3, while the deviation in total distance between harvest areas and ramps was 59.7 km. Scenario 5, with weights of 0.6 for volume and 0.4 for distance, produced these results, where compartments were closest to one another. The best scenario using the nonlinear model also produced a deviation in volume of 0 m3 and the total average deviation in distance between harvest areas and ramps was 8.7 km. Scenario 3, with weights of 0.8 for volume and 0.2 for distance, produced these results. The approach and models described through this study may be appropriate for further integration into forest management planning processes developed for the planning of Mediterranean forests.

Comparison of Forwarder Productivity and Optimal Road Density in Thinning and Clearcutting of Pine Plantation in Southern Brazil

volume: 43, issue:

The prescription of forest management determines the number of trees to be cut and, consequently, the harvested wood volume, which directly influences the forest operations dynamic. The objectives of this paper were (i) to analyze the effect of process factors on wood extraction performance with forwarder in first thinning and clearcutting of Pinus taeda L. plantations; and (ii) to economically determine the optimal road density to manage these plantations. Time and motion studies at the cycle element level were conducted to quantify and model the time consumption, productivity, and operational costs of the extraction. The optimal road density (ORD) for both operation types (OT) was determined based on the transport geometry model, considering the minimization of the sum of unitary costs with construction and maintenance of roads, loss of productive area, and wood extraction. The extraction distance (ED), slope (SL), average log volume (LV), and OT had a significant effect on the time consumed in travels, and therefore, on productivity (PPMH). In clearcutting, the average PPMH was 12.17 m3ob PMH0-1, while, in thinning, it was 10.94 m3ob PMH0-1; however, as the ED increased, the difference of PPMH and the cost of extraction between the operations decreased, which highlighted a greater effect of this factor on forwarder’s work in clearcutting. For this reason, the ORD for clearcutting (37.76 m ha-1) was higher than for thinning (27.84 m ha-1). Therefore, we demonstrated in this study that the type of operation and forest management regime, as well as their interaction with process factors, affect the sizing of the number of roads per unit area, and also the costs of the forest activity.


Web of Science Impact factor (2020): 2.088
Five-years impact factor: 2.077

Quartile: Q2 - Forestry

Subject area

Agricultural and Biological Sciences