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1.
《Scandinavian Journal of Forest Research》2012,27(7):635-642
ABSTRACTFarm tractor?+?trailers play a key role in wood transportation after forests are logged. Despite of the fact that a forwarder is a forestry vehicle that carries felled logs for shorter distances off the ground, tractors are still used in some forest areas of the world, such as the Hyrcanian forest in northern Iran. This study was conducted to investigate the possibility of using both the light forwarder and forestry trailer instead of a farm tractor?+?trailer in wood transportation. The optimal machine option for wood transportation is determined using goal programming model in the study area. In this paper, multi-objective goals (such as economic, operational, environmental and ergonomic) were considered. The results showed that considering only the economic goal, the contractor could save up to 44% in costs by purchasing and replacing a forestry trailer with a 2-wheel trailer attached to the farm tractor. In addition, considering various goals, a light forwarder could be selected as the optimal machine. Currently, the most important objectives of all forest contractors are to establish economic goals and reduce wood transportation costs. Since other goals, such as environmental and ergonomic, are also important; it is suggested that multi-objective approaches should use for planning. 相似文献
2.
Atsushi Yoshimoto 《Journal of Forest Research》1996,1(2):67-72
In the past studies on the Gentan probability theory, economic factors, such as the price of logs and the interest rate, have
not been embedded into the derived stochastic model due to the limitation of the underlying assumptions. This has lead to
misleading results of economic analysis for harvesting behavior based on the Gentan probability theory. In this paper, economic
analysis of harvesting behavior was conducted by extending the Gentan probability theory. Since the proposed stochastic process
can incorporate a nonstationary growth function, economic analysis of harvesting behavior was easily implemented. Experimental
analysis of economic factors showed that change in the price of logs, the interest rate and harvest related costs affected
the Gentan probability distribution. Although the analysis is still hypothetical, the results imply the potential use of the
Gentan probability theory to predict the forest owners' harvesting behavior. 相似文献
3.
Chikara Nakahata Kazuhiro Aruga Ryo Uemura Masashi Saito Kanae Kanetsuki 《Small-Scale Forestry》2014,13(2):251-266
This study examines the optimal method to extract logging residues from small, fragmented and scattered forests separately from the mechanized operational systems used on aggregated forestry operation sites. First, small-scale logging systems operated by a private logging contractor and an individual forest owner were investigated. Regression equations for estimating felling and processing cycle times were established as a function of stem and log volumes, respectively. Equations to estimate the forwarding and transporting cycle times were established as a function of the forwarding and transporting distances using the forwarding and transporting velocities, respectively. Then, equations to estimate productivities and costs were established with the cycle times, volumes and hourly operational expenses consisting of labour and machinery expenses. Finally, costs of the small-scale systems—mini-forwarder and 4 t truck operated by a private logging contractor, and manual logging and light truck operated by an individual forest owner—were estimated and compared with the mechanized operation system operated by the Forest Owners’ Association. The mechanized operation system was found to have the highest cost and could not compete for small forestry operational sites and small stem volumes. The small-scale systems could be effective for harvesting small areas. This was especially true when conducting extracting operations without machines, as done by the individual forest owner, and transporting operations by a private logging contractor, in which the hourly income of the individual forest owner was higher than the hourly labour expenses. 相似文献
4.
There is increasing interest worldwide in using tree harvesting biomass as an energy source. Bark retained on logs is commonly used as an energy source, but is generally removed from eucalypt logs during harvest. In order to evaluate the potential use of eucalypt bark as fuel, there is a need for information on the productivity and cost implications of retaining eucalypt bark during harvest operations. The study examined the impact of retaining bark on logs on the productivity and costs of a whole?tree to roadside harvesting system in a short?rotation Eucalyptus nitens plantation in Australia being harvested for pulp logs. Trees were felled and bunched with a feller?buncher in spring, then left infield for four weeks to promote bark adhesion and reduce bark loss. A skidder extracted the trees to roadside where a processor processed them to predominantly 10?m logs. Machine productivities were calculated from estimated tree and log volumes and cycle times recorded from video recordings. The feller?buncher's productivity (65 m3 PMH0?1) was less than expected as it appeared to be underpowered to handle the larger trees on the study site. The skidder's productivity (56 m3 PMH0?1) was comparable to those reported in studies under similar conditions and with bark retained. The roadside processor's productivity (25 m3 PMH0?1) was lower than expected. This was believed to result from the operator separately stacking 10?m and 5?m logs, and the lower feed speed resulting from slippage due to the reduced feed roller pressure used in the study to reduce bark loss. Future research could identify feed rollers that increase feed speed while retaining bark. Harvest system costs (AUD18 GMt?1) were similar to those reported for a eucalypt roadside processing trial where bark was removed. These results suggest that retaining bark on the logs at roadside did not affect the harvesting system's productivity or costs. 相似文献
5.
基于GIS的木材运输计划决策支持系统 总被引：9，自引：3，他引：9
制定木材运输计划需要大量的空间和非空间数据。基于GIS的木材运输计划决策支持系统 ,对线性规划和GIS技术进行集成 ,以运材费与集材费的综合费用为寻找最小费用路径和最佳楞场空间位置的目标函数 ,建立线性规划模型。运输费、可采木材材积和木材定货量等模型参数以MPS文件格式存储 ,实现LINDO与系统间的数据交换。系统是制定木材运输计划的有效工具 ,也为编制作业计划提供重要的基础数据 相似文献
6.
We estimate economic cost functions for timber harvesting, transportation and milling in the Brazilian Amazon using a 2003 sample of 527 firms in both new and older frontier locations. We find that labor wage, distance from the forest to the processing location, type of equipment, and the type of the frontier all factor significantly in the total and marginal cost of each activity, and that predicted processing costs are not significantly different on new frontiers implying a lack of technology adoption as industry expansion into the Amazon has occurred. We also show that capturing economies of scale in logging by increasing average annual logging volumes by 50% and reducing the number of firms to about 1400 could lead to an industry wide cost savings of approximately US$90 million per year. Similar economies of scale are also present in log transport but not in processing. Further, if improved logging techniques allow harvest for an additional 1 month per year, for example through better planning, the industry could reduce logging costs by almost US$30 million. This points towards generating forest policies and economic conditions that encourage firm size growth, as opposed to those policies encouraging massive entry of small, unregulated and inefficient firms, and the adoption of management practices that allow for additional time in the forest. 相似文献
7.
8.
A mature, average stand of European beech was generated based on characteristic data of trial plots. Some 27 different strategies of target diameter harvest, were simulated for up to 80 years with the help of a distance-dependent single-tree growth simulator. The treatments were differing in the size of the target diameter, the beginning and the end of the harvest. Based on a statistical model, the probability of the occurrence of more than 30% of red heartwood at the front-side diameter was calculated for three sections of each log. Using the predicted probability, the decrease of timber quality due to red heartwood for different treatment strategies was assessed. The harvested volume and the predicted timber quality for different harvesting strategies were used to calculate the net revenue achieved in each simulation period with the help of a calculation program. The net present value for variable interest rates of the different harvesting strategies was calculated, assuming free land rent. Using a linear programming approach, optimal areas for different treatment strategies of a modelled forest of 100 ha were calculated under 4 different scenarios. The results of the optimisation showed how the increasing interest rates replaced higher target diameters out of the optimal solution. In contrast to that the treatments with higher target diameter became more important with increasing restrictions concerning budget or ecological constraints. 相似文献
9.
Sustained yield policies designed to ensure an even annual flow of timber harvests remain the most common approach to forest management on public lands in Canada. Such policies have been criticized on the environmental grounds that timber production is emphasized at the expense of other values, and on the economic grounds that policy-makers try to maximize the harvests level without regard for economic optimality (measured by whether or not revenues cover variable costs of production). In a case study from Northern Ontario, we used a spatially explicit harvest scheduling model to evaluate financial outputs for various scenarios, introducing different timber flow constraints, as well as varying utilization policies. We show that current policies do contribute to firms harvesting at uneconomic levels. More specifically, our results show that reducing harvest levels could increase firm profitability (measured in an increase in net revenues associated with harvesting operations). We estimate that to meet the annual allowable cut (AAC) of approximately 375,000 cubic metres (m3), the firm loses $500,000 annually (measured by the amount by which total harvesting costs exceed log values delivered at the mill). Reducing the target AAC to just under 300,000 m3 leads to a reversed situation, harvesting revenues now exceeding costs by $1.2 million annually. Dropping the even flow constraint leads to even higher annual profitability of $3.5 million, with the drawback that harvesting levels show significant variation over the 100-year planning period. Our results also show that the largest factor influencing the level of profitability is attributed to access costs (principally roading costs). In this case, other harvesting policies, such as utilization standards, may not be significant factors affecting costs in this region of Northern Ontario. 相似文献
10.
Atsushi Yoshimoto 《Journal of Forest Research》2002,7(2):81-90
In this paper, a stochastic control model is constructed by incorporating geometric Brownian motion to capture uncertain price
dynamics into a one-stage and two-state stochastic dynamic programming model. The proposed model is designed to search for
optimal harvest timing under price uncertainty without considering other forestry operations,e.g., thinning. We consider the option of abandoning forest management for an alternative use of forest land besides replantation.
Our experimental analysis shows that the optimal harvest timing under stochastic log prices is delayed when a price level
is crucially low for maintaining the management. It is also shown that when the current log price is sufficiently high, the
optimal harvest timing derived from both the stochastic and deterministic approach becomes the same. With a downward trend
of stochastic price dynamics, the optimal harvest timing tends to be hastened overall. This is because of the depreciation
effect on the future return, which stimulates harvesting in an earlier period.
This research was supported by a Grant-in-Aid for Scientific Research (No.11660155) from the Ministry of Education, Culture,
Sports, Science and Technology of Japan. 相似文献
11.
12.
This study assessed aspen regeneration on decking areas as affected by season of log deck building and duration of log storage;
as well as root wounding, soil compaction, and slash depth. On former decking areas that were built after a summer harvest,
aspen regeneration was 50% lower and root death 35% greater compared to former decking areas of a fall harvest. Duration of
log storage after a fall harvest had little effect on aspen regeneration; short (1.5–3 months) or long (11 months) storage
resulted in similar regeneration. Slash load was greatly increased on decking areas while root wounding and soil bulk density
were only slightly increased compared to controls. For best management practices, log storage after summer harvest should
be avoided especially when logs are kept over the growing period when suckering occurs. Additionally, removing the interwoven
mat of slash covering decking areas and limiting machine traffic to frozen soil will ensure vigorous suckering. 相似文献
13.
The spatial allocation of harvesting activities is a challenging task for forest managers, given the complexity of coordinating operations and the great contribution of harvesting to the total cost of wood production. Traditionally, forest harvesting policies have intended to limit maximum clear-cut areas, leading to harvesting fragmentation, and have thus reduced interior forest habitat and negatively affected operational efficiency. Aiming to address this issue, the main goals of this study were i) to propose approaches to include harvesting connectivity into a forest planning model, and ii) to evaluate the impacts of enforcing connectivity on the economic outcomes of the forest. We applied two approaches for clustering forest harvesting: (i) a model based on the Minimum Spanning Tree problem for enforcing harvesting connectivity and (ii) a Simulated Annealing approach for simultaneous consideration of harvesting stands connectivity and wood flow. The optimization process could reduce the average harvesting radius from 4575.8 up to 2300.5 m and increase the average area of harvesting blocks from 22.4 up to 157.4 ha. However, this solution would marginally reduce the net present values (from 3.9% to 15.4%) compared to the base scenario, without the inclusion of connectivity requirements and depending on the level of enforced connectivity. 相似文献
14.
We used a goal programming technique to determine the optimal harvest volume for the Iranian Caspian forest. We collected data including volume, growth, wood price at forest roadside, and variable harvesting costs. The allometric method was used to quantify seques- trated carbon. Regression analysis was used to derive growth models. Expected mean price was estimated using wood price and variable harvesting costs. Questionnaire was used to determine the constraints and the equation coefficients of the goal programming model. The optimal volume was determined using the goal programming method according to multipurpose forest management. LINGO software was used for analysis. Results indicated that the optimum volumes of species were 250.25 m3.ha-1 for beech, 59 m3.ha-1 for hornbeam, 73 m3.ha-1 for oak, 41 m3.ha-1 for alder, and 32 m3.ha-1 for other species. The total optimum volume is 455.25 m3.ha-1. 相似文献
15.
Emin Zeki Başkent Ali İhsan Kadıoğulları 《Scandinavian Journal of Forest Research》2014,29(7):121-131
Decision support systems (DSSs) are indispensable tools in preparing a forest management plan for a better combination of multiple forest values. This study attempted to develop and explain a stand-based forest management DSS (Ecosystem-based multiple-use forest planning [ETÇAP]) comprising a traditional simulation, linear programming (LP), metaheuristics and geographic information system. The model consists of five submodels; traditional management approach to handle inventory data, an empirical growth and yield model, a simulation to conceptualize management actions, a LP technique to optimize resource allocation and a simulated annealing approach to directly create a spatially feasible harvest schedule. The ETÇAP model has been implemented in a comparative two case study areas; Denizli–Honaz and Akseki–Ibrad?. Both simulation and optimization models outperformed to the traditional management plan. The periodical change of growing stock, allowable cuts, carbon sequestration and water production are used as performance indicators. The results showed that more amount of wood could be harvested over time compared to traditional level of harvesting. It could be concluded that various management strategies allowed managers to stimulate more decision options for better outputs through intertemporal trade-offs of management interventions as the model provided tools to quantify forest dynamics over time and space. Challenges exist to establish the functional relationships between forest structure and values for better quantification and integration into the management plans. 相似文献
16.
One of the classic operations problems in forest management is to select the harvesting system and to plan the layout, which has a significant impact on overall operational and environmental efficiency. This paper addresses the design of a harvesting system in areas characterized by steep slopes requiring cable-based harvesting under central European conditions. We present two computationally efficient methods (designated as set-covering model SCM and bounded set-covering model BSCM) for solving problems of cable road layouts and comparing them with a previously developed model (CaMLOC). Formulating the problem as a type of location set-covering model allowed us to delineate a much smaller problem that was easier to solve. By applying the new model formulations, it is possible to identify mathematical optimal CR layouts for real-world forests areas up to 50 ha within a reasonable period of time and to even estimate the maximum gap in optimality (only with the BSCM approach). 相似文献
17.
An integrated assessment approach to optimal forest bioenergy production for young Scots pine stands
《Forest Ecosystems》2015,(3)
Background: Bioenergy is re-shaping opportunities and imperatives of forest management. This study demonstrates,through a case study in Scots pine(Pinus sylvestris L.), how forest bioenergy policies affect stand management strategies.Methods: Optimization studies were examined for 15 Scots pine stands of different initial stand densities, site types, and temperature sum regions in Finland. Stand development was model ed using the Pipe Qual stand simulator coupled with the simulation-optimization tool Opti For Bioenergy to assess three forest bioenergy policies on energy wood harvest from early thinnings.Results: The optimal solutions maximizing bare land value indicate that conventional forest management regimes remain optimal for sparse stands. Energy harvests occurred only when profitable, led to lower financial returns. A forest bioenergy policy which included compulsory energy wood harvesting was optimal for denser stands. At a higher interest rate(4 %), increasing energy wood price postponed energy wood harvesting. In addition, our results show that early thinning somewhat reduced wood quality for stands in fertile sites. For less fertile sites, the changes were insignificant.Conclusions: A constraint of profitable energy wood harvest is not rational. It is optimal to carry out the first thinning with a flexible forest bioenergy policy depending on stand density. 相似文献
18.
Staffan Berg Janine Schweier Franka Brüchert Marcus Lindner Erik Valinger 《Scandinavian Journal of Forest Research》2014,29(5):485-498
The forest sector is important for the German Federal State of Baden-Württemberg (BW) and the Västerbotten (VB) County in Sweden. Their forestry wood chains (FWCs) are of similar magnitude and supply forest industries. This study provides a regional comparison of the performance of FWCs from roundwood harvesting, including hauling, to mill gate concerning the factors that impact sustainability and assess different sustainability indicators for alternative supply chains, in particular fully mechanized chains in comparison to motor-manual operations. The harvest volumes are similar but operational conditions differ. Analysis of sustainability indicators demonstrated that the total costs for roundwood to industry are similar. Higher harvesting costs in BW are compensated for by lower transport costs to the mills. Employment per unit is higher in BW because of the high share of labour in felling. Due to smaller machinery and shorter transport distances in BW, energy use and greenhouse gas emissions per unit are lower than in VB. Areas for improvement are the technologies for logging in BW and the logistics of timber transport in VB. 相似文献
19.
In strategic level planning, the harvest levels are often obtained by maximizing NPV of the forest area. The resulting harvests within each planning period are then typically scattered over the area. In practical forestry, clustering harvests is seen as important, but tools for planning harvest clustering applicable for practical level planning are largely missing. In previous studies, clustering harvests has been seen as an objective in itself rather than means to save costs. It has thus not been possible to define an optimal level for clustering in order to maximize the NPV. In this study, clustering is carried out by minimizing the total opening costs (TOCs) for harvest sites. TOC is defined as a fixed cost for one contiguous harvest cluster. It consists of e.g. transferring the machines to the harvest site, waiting time for the machinery and workers due to the transfer, delineation of the harvest site and administrative work required for each harvest site. Our results show that with small opening cost, it is optimal to follow the strategic level plan, while as the opening cost increases it is optimal to make larger and larger harvest clusters. The clustering also affects the treatments carried out: with high opening costs the harvests in some stands will be postponed for 10 years or more, or the treatment may change from the strategic level optimum. 相似文献
20.
《Journal of Sustainable Forestry》2013,32(3-4):93-118
Abstract In planning of sustainable forest management, economic, environmental and social demands often conflict. Forest management in Southeast Asian tropical dipterocarp forests has been particularly biased towards maximizing immediate economic return from extensive logging. Overexploitation and other forms of uncontrolled land use within these forests have led to the situation where the remaining natural forests, most of them in Indonesia, will be liquidated within the next 10-15 years at the current rate of deforestation. In this paper we present an approach for sustainable forest management planning in which economic, environmental and social sustainability are considered simultaneously in order to define an optimal management strategy from a set of available alternatives. We carried out a case study within a rain forest logging concession in Indonesian Borneo by using a participatory planning approach involving interviews of the local people, environmental assessment and economic analyses. We used the Analytic Hierarchy Process (AHP) method for resource allocation and priority setting in order to identify an optimal strategy which yields a sustained economic output from timber production, while at the same time being environmentally and socioculturally sustainable. Despite their relatively high costs, strategies involving selective harvesting combined to complete restoration of original dipterocarp stock in logged-over areas were superior in terms of economic, environmental and social sustainability. Priorities set by local communities for the strategies to meet their socioeconomic and cultural needs coincide well with those ensuring the restoration and biodiversity. 相似文献