Category: Research article
article id 10309, category Research article
Comprehensive yield model for plantation teak in Panama. Silva Fennica vol. 54 no. 5 article id 10309. https://doi.org/10.14214/sf.10309
Highlights: Tree level teak stem volume models, taper model and three sets of stand level yield models were developed using large empirical datasets; Tree volume models were satisfactorily validated against independent measurement data and other published models; Tree height as input parameter improved the stem volume model marginally; Stand level yield models produced comparable harvest volumes with models published in the literature; Stand level timber product outputs were found like actual harvests with an exception that the models marginally underestimate the share of logs in very large diameter classes.
The purpose of this study was to prepare a comprehensive, computerized teak (Tectona grandis L.f) plantation yield model system that can be used to describe the forest dynamics, predict growth and yield and support forest planning and decision-making. Extensive individual tree and permanent sample plot data were used to develop tree-level volume models, taper curve models and stand-level yield models for teak plantations in Panama. Tree volume models were satisfactorily validated against independent measurement data and other published models. Tree height as input parameter improved the stem volume model marginally. Stand level yield models produced comparable harvest volumes with models published in the literature. Stand level volume product outputs were found like actual harvests with an exception that the models marginally underestimate the share of logs in very large diameter classes. The kind of comprehensive model developed in this study and implemented in an easy to use software package provides a very powerful decision support tool. Optimal forest management regimes can be found by simulating different planting densities, thinning regimes and final harvest ages. Forest practitioners can apply growth and yield models in the appropriate stand level inventory data and perform long term harvest scheduling at property level or even at an entire timberland portfolio level. Harvest schedules can be optimized using the applicable financial parameters (silviculture costs, harvesting costs, wood prices and discount rates) and constraints (market size and operational capacity).
article id 10074, category Research article
Optimal location of laminated beech production plants within the solid hardwood supply network in Austria. Silva Fennica vol. 53 no. 3 article id 10074. https://doi.org/10.14214/sf.10074
Highlights: This paper provides data to the solid hardwood business and develops a mixed integer linear program model to design a laminated beech wood supply network; It covers the strategic decision where to locate a new production facility within the existing supply network with the lowest supply network cost; Sufficient sawn wood suppliers and potential facility locations are provided.
Due to changes in forest management in various European countries, hardwood forest areas and amounts will increase. Sustainable and individual utilization concepts have to be developed for the upcoming available resource. Studies conclude that there is low potential for hardwoods in the traditional appearance market thus the application areas have to be extended to new structural innovative products. This paper examines the extension to a future laminated beech wood supply network which would be a combination of already existing and new production facilities. For a better future use of hardwood raw materials it is necessary to consider the entire supply chain. This also better shows a total hardwood value chain. Therefore, this paper provides data to the solid hardwood business and develops a mixed integer linear programming to design a laminated beech wood supply network. The model is applied to Austria as the sample region. It covers the important strategic decisions where to locate a downstream facility within the existing production network with the lowest supply network cost. Fourteen scenarios are developed to examine various future network configurations. Results about optimal material flows and used sawmills as well as downstream production facilities are presented in form of material and financial performances. Two optimal laminated beech production locations are determined by the calculated scenarios results, and the impact of a new sawmill is analyzed which is focused on beech.
article id 2018, category Research article
Influence of soil type, cartographic depth-to-water, road reinforcement and traffic intensity on rut formation in logging operations: a survey study in Sweden. Silva Fennica vol. 51 no. 5 article id 2018. https://doi.org/10.14214/sf.2018
Highlights: Soil type and traffic intensity had significant effects on rut formation; Further studies are required to identify all factors affecting rut formation, especially on soils with medium bearing capacity; The cartographic depth-to-water index (DTW) alone did not predict rut formation, but used in combination with other information, e.g. soil type, could be an interesting tool for delineating soil areas that are potentially vulnerable to rut formation in logging operations.
Rut formation caused by logging operations has been recognised as a challenge for Swedish forestry. Frequent traffic with heavy machines on extraction roads, together with a warmer climate, is one of the factors that increases the risk of rut formation in forests. One possible way to control this impact of logging operations is to design and apply decision support tools that enable operators to take sensitive areas into account when planning extraction roads. In this study, 16 different logging sites in south-eastern Sweden were surveyed after clear-cut. Information was collected about extraction roads (i.e. traffic intensity, whether the roads had been reinforced with slash) and ruts. Digital maps such as cartographic depth-to-water (DTW) index and soil type were also examined for any connection to rut positions. Soil type and traffic intensity were found to be significant factors in rut formation, while DTW and slash reinforcement were not. However, the DTW map combined with other information, such as soil type, could contribute to decision support tools that improve planning of extraction roads.
article id 1778, category Research article
Quantifying and resolving conservation conflicts in forest landscapes via multiobjective optimization. Silva Fennica vol. 51 no. 1 article id 1778. https://doi.org/10.14214/sf.1778
We introduce a compatibility index quantifying how targeting a management objective in the forest landscape affects another objective; To resolve conflicts we find compromise solutions minimizing the maximum deterioration among objectives; We apply our approach for a case study of forest management for biodiversity conservation and development; Multiple use management and careful planning can reduce biodiversity conflicts in forest ecosystems.
Environmental planning for of the maintenance of different conservation objectives should take into account multiple contrasting criteria based on alternative uses of the landscape. We develop new concepts and approaches to describe and measure conflicts among conservation objectives and for resolving them via multiobjective optimization. To measure conflicts we introduce a compatibility index that quantifies how much targeting a certain conservation objective affects the capacity of the landscape for providing another objective. To resolve such conflicts we find compromise solutions defined in terms of minimax regret, i.e. minimizing the maximum percentage of deterioration among conservation objectives. Finally, we apply our approach for a case study of management for biodiversity conservation and development in a forest landscape. We study conflicts between six different forest species, and we identify management solutions for simultaneously maintaining multiple species’ habitat while obtaining timber harvest revenues. We employ the method for resolving conflicts at a large landscape level across a long 50-years forest planning horizon. Our multiobjective approach can be an instrument for guiding hard choices in the conservation-development nexus with a perspective of developing decision support tools for land use planning. In our case study multiple use management and careful landscape level planning using our approach can reduce conflicts among biodiversity objectives and offer room for synergies in forest ecosystems.
article id 1414, category Research article
Local pivotal method sampling design combined with micro stands utilizing airborne laser scanning data in a long term forest management planning setting. Silva Fennica vol. 50 no. 2 article id 1414. https://doi.org/10.14214/sf.1414
Highlights: Most similar neighbor imputation was used to estimate forest variables using airborne laser scanning data as auxiliary data; For selecting field reference plots the local pivotal method (LPM) was compared to systematic sampling design; The LPM sampling design combined with a micro stand approach showed potential for improvement and has the potential to be a competitive method when considering cost efficiency.
A new sampling design, the local pivotal method (LPM), was combined with the micro stand approach and compared with the traditional systematic sampling design for estimation of forest stand variables. The LPM uses the distance between units in an auxiliary space – in this case airborne laser scanning (ALS) data – to obtain a well-spread sample. Two sets of reference plots were acquired by the two sampling designs and used for imputing data to evaluation plots. The first set of reference plots, acquired by LPM, made up four imputation alternatives (varying number of reference plots) and the second set of reference plots, acquired by systematic sampling design, made up two alternatives (varying plot radius). The forest variables in these alternatives were estimated using the nonparametric method of most similar neighbor imputation, with the ALS data used as auxiliary data. The relative root mean square error (RelRMSE), stem diameter distribution error index and suboptimal loss were calculated for each alternative, but the results showed that neither sampling design, i.e. LPM vs. systematic, offered clear advantages over the other. It is likely that the obtained results were a consequence of the small evaluation dataset used in the study (n = 30). Nevertheless, the LPM sampling design combined with the micro stand approach showed potential for improvement and might be a competitive method when considering the cost efficiency.
article id 116, category Research article
Multiple criteria decision analysis with consideration to place-specific values in participatory forest planning. Silva Fennica vol. 45 no. 2 article id 116. https://doi.org/10.14214/sf.116
The combination of multiple criteria decision analysis (MCDA) and participatory planning is an approach that has been applied in complex planning situations where multiple criteria of very different natures are considered, and several stakeholders or social groups are involved. The spatial character of forest planning problems adds further to the complexity, because a large number of forest stands are to be assigned different treatments at different points in time. In addition, experience from participatory forest planning indicates that stakeholders may think about the forest in terms of place-specific values rather than in forest-wide terms. The objective of this study was to present an approach for including place-specific values in MCDA-based participatory forest planning and illustrate the approach by a case study where the objective was to choose a multipurpose forest plan for an area of urban forest in northern Sweden. Stakeholder values were identified in interviews, and maps were used to capture place-specific spatial values. The nonspatial and nonplace-specific spatial values were formulated as criteria and used to build an objective hierarchy describing the decision situation. The place-specific spatial values were included in the creation of a map showing zones of different silvicultural management classes, which was used as the basis for creation of forest plan alternatives in the subsequent process. The approach seemed to work well for capturing place-specific values, and the study indicates that formalized methods for including and evaluating place-specific values in participatory forest planning processes should be developed and tested further.
article id 238, category Research article
Forest owners' decision support in voluntary biodiversity-protection projects. Silva Fennica vol. 42 no. 4 article id 238. https://doi.org/10.14214/sf.238
New forest-biodiversity-protection instruments based on temporary protection periods and non-industrial private forest owners’ voluntary participation have been recently introduced and tested in pilot areas located in Southern Finland. Thanks to their several benefits, the use of voluntary instruments is becoming more common in many other countries as well. Voluntary protection here means that forest owners voluntarily set aside tracts of forest to be protected and define their compensation fees. Depending on the objectives of the forest owners, the compensation fee reflects the forest owners’ (positive) attitude towards biodiversity, scenic beauty, recreational values and/or the existence of long-term cutting possibilities. When a forest owner decides to offer part of his/her forest holding to be temporarily protected, the owner faces a new decision problem related to definition of the compensation fee, which should be based on diverse information concerning stand- and holding-level opportunity costs as well as on the biodiversity value of the stand. This article introduces three decision-support elements for assisting forest owners in defining their compensation fees. The first element relates to the assessment of the potential stand-level loss of timber harvesting income that the temporary protection of the stand may cause. The second element sets the holding-level opportunity cost of protection by utilizing the forest owners’ holding level goals, the holdings’ production possibilities and optimization methods. The third element describes the biodiversity value of the stand by means of a multi-criteria expert model. Case study material collected from the area of Central Karelia Herb-rich Forests Network pilot project is used to illustrate the characteristics of the decision-support elements and to point out some development needs for the future use of these elements.
article id 357, category Research article
Scheduling forest road maintenance using the analytic hierarchy process and heuristics. Silva Fennica vol. 40 no. 1 article id 357. https://doi.org/10.14214/sf.357
The management of low-volume roads has transitioned from focusing on maintenance designed to protect a capital investment in road infrastructure to also include environmental effects. In this study, two models using mathematical programming are applied to schedule forest road maintenance and upgrade activities involving non-monetary benefits. Model I uses a linear objective function formulation that maximizes benefit subject to budgetary constraints. Model II uses a non-linear objective function to maximize the sum of benefits divided by the sum of all costs in a period. Because of the non-linearity of the constraints and the requirements that the decision variables be binary, the solutions to both problem formulations are found using two heuristics, simulated annealing and threshold accepting. Simulated annealing was found to produce superior solutions as compared to threshold accepting. The potential benefit for completing a given road maintenance or upgrade project is determined using the Analytic Hierarchy Process (AHP), a multi-criterion decision analysis technique. This measure of benefit is combined with the economic cost of completing a given project to schedule maintenance and upgrade activities for 225 km (140 miles) of road in forested road systems within western Oregon. This combination of heuristics, cost-benefit analysis, environmental impacts, and expert judgment produces a road management schedule that better fits the current road management paradigm.
article id 363, category Research article
Comparison of human and computer-based selective cleaning. Silva Fennica vol. 39 no. 4 article id 363. https://doi.org/10.14214/sf.363
In silvicultural tending operations like cleaning (pre-commercial thinning), the results are irreversible, so it is important for the decisions to be consistent with the aims for the stand. To enable operational automatic stem selections, a decision support system (DSS) is needed. A previously presented DSS seems to render acceptable cleaning results, but needs further analysis. The aims of the study were to compare the cleaning results of experienced cleaners and DSS simulations when “similar” instructions were given, and to assess the usefulness and robustness of the DSS. Twelve experienced cleaners were engaged to “clean” (mark main stems) six areas; each cleaner “cleaned” two areas. The DSS was used to generate two computer-based cleanings (simulations) of these areas. Four laymen also “cleaned” one of the areas following the DSS. The density results were significantly affected by the areas’ location, whereas the proportions of deciduous stems and damaged stems were significantly affected by both the areas’ location and method, i.e. manual “cleaning” and general or adjusted simulation. The study showed that the DSS can be adjusted so that the results are comparable with the cleaners’ results. Thus, the DSS seems to be useful and flexible. The laymen’s results were close to the results of the “general” simulation, implying that the DSS is robust and could be used as a training tool for inexperienced cleaners. The DSS was also acceptable on a single-tree level, as more than 80% of the main-stems selected in the simulations were also selected by at least one cleaner.
article id 387, category Research article
Evaluation of the multicriteria approval method for timber-harvesting group decision support. Silva Fennica vol. 39 no. 2 article id 387. https://doi.org/10.14214/sf.387
The decision support methods most often used in timber-harvesting planning are based on a single criterion. In this study, a voting-theory-based method called multicriteria approval (MA) is introduced to the group decision support of timber-harvesting. The use of voting methods alleviates the problems caused by the multitude of decision objectives involved in forestry decision-making and by the poor quality of information concerning both the preferences of decision-makers and the evaluation of decision alternatives with respect to the objectives often faced in practical timber-harvesting planning. In the case study, the tactical forest management plan of a forest holding jointly owned by three people was specified at the operative timber-harvesting level. The task was to find the best actual operative alternatives for the harvesting that had been proposed in the tactical plan. These timber-harvesting alternatives were combinations of treatment, timber-harvesting system and the timing of logging. Forest owners established multiple criteria under which the alternatives were evaluated. Two versions of MA were tested, one of them based on individual decision analyses and other one based on a composite analysis. The first was markedly modified from the original MA, combining properties of MA and Borda count voting. The other was an original MA with the order of importance for criteria estimated either using Borda count or cumulative voting. The results of the tested MA versions produced were very similar to each other. MA was found to be a useful tool for the group decision support of timber-harvesting.
article id 597, category Research article
Outranking methods as tools in strategic natural resources planning. Silva Fennica vol. 35 no. 2 article id 597. https://doi.org/10.14214/sf.597
Two outranking methods, ELECTRE III and PROMETHEE II, commonly used as decision-aid in various environmental problems, and their applications to decision support for natural resources management are presented. These methods represent ‘the European school’ of multi-criteria decision making (MCDM), as opposed to ‘the American school’, represented by, for instance, the AHP method. On the basis of a case study, outranking methods are compared to so far more usually applied techniques based on the ideas of multi attribute utility theory (MAUT). The outranking methods have been recommended for situations where there is a finite number of discrete alternatives to be chosen among. The number of decision criteria and decision makers may be large. An important advantage of outranking methods, when compared to decision support techniques most often applied in today’s natural resources management, is the ability to deal with ordinal and more or less descriptive information on the alternative plans to be evaluated. Furthermore, the uncertainty concerning the values of the criterion variables can be taken into account using fuzzy relations, determined by indifference and preference thresholds. The difficult interpretation of the results, on the other hand, is the main drawback of the outranking methods.
article id 621, category Research article
Integrating timber price scenario modeling with tactical management planning of private forestry at forest holding level. Silva Fennica vol. 34 no. 4 article id 621. https://doi.org/10.14214/sf.621
In forest management planning, deterministic timber prices are typically assumed. However, real-life timber prices vary in the course of time, and also price peaks, i.e. exceptionally high timber prices, might occur. If land-owners can utilise the price variation by selling timber with the high prices, they are able to increase their net revenues correspondingly. In this study, an approach is presented to study the timber price variation and its significance in the optimization of forest management. The approach utilizes stochastic timber price scenario modelling, simulation of forest development, and optimization of forest management. The approach is presented and illustrated by means of a case study. It is shown how the degree of uncertainty due to variation in timber prices can be analyzed in tactical forest planning of private forestry, and how the potential benefits of adaptive timber-selling behaviour for a forest landowner can be computed by using the approach. The effects of stochastic timber prices on the choice of forest plan are studied at the forest holding level considering also the spacing and type of cuttings and the optimal cutting order. A forest plan prepared under the assumption of constant timber price very seldom results in optimal forest management. Through studying the effects of stochastic timber prices, forest landowners and other decision makers obtain valuable information about the significance of adaptive timber selling behaviour. The presented methodology can also be used in analysing the land-owners’ economic risks as a function of time-price structure.
article id 698, category Research article
Satisfaction and company loyalty as expressed by non-industrial private forest owners towards timber procurement organizations in Finland. Silva Fennica vol. 32 no. 1 article id 698. https://doi.org/10.14214/sf.698
The satisfaction and company loyalty as expressed by non-industrial, private forest (NIPF) owners towards timber procurement organizations were clarified via a mail questionnaire. The results denoted that there is a positive correlation between the levels of forest owners’ expectations (EXP) and perceived performance (PERF). In addition, the lower EXP and the higher PERF were, the greater was the overall satisfaction index (SAT). About two thirds of forest owners were characterized by a negative SAT value or then they were dissatisfied with the performance of the procurement organization in their last timber-sales transaction. Furthermore, the results obtained indicated that the SAT index significantly influences the company loyalty expressed by NIPF owners – their willingness to give favourable reports of the company to the others, and their willingness to engage in future timber-sales transactions with the same company. Nonetheless, the SAT index did not affect the market share of a particular company, and this could be partly accounted for by the similar level of performance among the companies and the lack of competition in the timber trade. Finally, the results revealed several dimensions of timber procurement, and some seller segments to which companies could pay more attention to in order to be able to achieve better satisfaction levels and the loyalty of NIPF owners in the future. One approach to successfully addressing these challenges could be the adopting of a satisfaction decision support system (SatDSS).
Category: Review article
article id 9984, category Review article
Discrete event simulation of multimodal and unimodal transportation in the wood supply chain: a literature review. Silva Fennica vol. 52 no. 4 article id 9984. https://doi.org/10.14214/sf.9984
Highlights: Focus on discrete event simulation, wood supply chain and multimodal transport; Analyses of 12 review articles and a core of 32 research papers, complemented by 48 related ones; Research focus from unimodal to multimodal transport to build efficient, resilient, green and socially sustainable supply chains; Development of robust risk management considering supply risks, demand risks and external risks is needed.
This review systematically analyses and classifies research and review papers focusing on discrete event simulation applied to wood transport, and therefore illustrates the development of the research area from 1997 until 2017. Discrete event simulation allows complex supply chain models to be mapped in a straightforward manner to study supply chain dynamics, test alternative strategies, communicate findings and facilitate understanding of various stakeholders. The presented analyses confirm that discrete event simulation is well-suited for analyzing interconnected wood supply chain transportation issues on an operational and tactical level. Transport is the connective link between interrelated system components of the forest products industry. Therefore, a survey on transport logistics allows to analyze the significance of entire supply chain management considerations to improve the overall performance and not only one part in isolation. Thus far, research focuses mainly on biomass, unimodal truck transport and terminal operations. Common shortcomings identified include rough explanations of simulation models and sparse details provided about the verification and validation processes. Research gaps exist concerning simulations of entire, resilient and multimodal wood supply chains as well as supply and demand risks. Further studies should expand upon the few initial attempts to combine various simulation methods with optimization.
article id 5619, category Article
Decision support systems in wood procurement. A review. Silva Fennica vol. 31 no. 2 article id 5619. https://doi.org/10.14214/sf.a8520
Many kinds of planning systems have been labelled decision support systems (DSS), but few meet the most important features of real DSSs in planning and control of wood procurement. It has been concluded that many reasons exist to develop DSSs for wood procurement. The purchasing of timber seems to be one of the most promising areas for DSS, because there is no formal structure for these operations and decisions deal with human behaviour. Relations between DSSs and different features of the new approaches in wood procurement are also discussed, and hypotheses for future studies suggested.