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We analyzed the economics of mobile chipping and transport of biomass from forest residues for energy purposes under uncertainty. A discrete-event simulation model was developed and utilized to quantify the impacts of controllable and environmental variables on productivity in order to determine the most cost effective transportation options under steep terrain conditions. Truck-chipper interactions were analyzed to show their effect on truck and chipper standing time. A costing model was developed to account for operating and standing time cost (for the chipper and trucks). The model used information from time studies of each activity in the productive cycle and spatial-temporal information obtained from geographic information system (GIS) devices, and tracking analysis of machine and truck movements. The model was validated in field operations, and proved to be accurate in providing the expected productivity. A cost distribution was elaborated to support operational decisions of forest managers, landowners and risk-averse contractors. Different scenarios were developed to illustrate the economic effects due to changes in road characteristics such as in-highway transport distance, in-forest internal road distance and pile to trailer chipper traveling distances.

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.

As both spatial and temporal characteristics of desired future conditions are becoming important measures of forest plan success, forest plans and forest planning goals are becoming complex. Heuristic techniques are becoming popular for developing alternative forest plans that include spatial constraints. Eight types of heuristic planning techniques were applied to three increasingly difficult forest planning problems where the objective function sought to maximize the amount of land in certain types of wildlife habitat. The goal of this research was to understand the relative challenges and opportunities each technique presents when more complex difficult goals are desired. The eight heuristic techniques were random search, simulated annealing, great deluge, threshold accepting, tabu search with 1-opt moves, tabu search with 1-opt and 2-opt moves, genetic algorithm, and a hybrid tabu search / genetic algorithm search process. While our results should not be viewed as universal truths, we determined that for the problems we examined, there were three classes of techniques: very good (simulated annealing, threshold accepting, great deluge, tabu search with 1-opt and 2-opt moves, and tabu search / genetic algorithm), adequate (tabu search with 1-opt moves, genetic algorithm), and less than adequate (random search). The relative advantages in terms of solution time and complexity of programming code are discussed and should provide planners and researchers a guide to help match the appropriate technique to their planning problem. The hypothetical landscape model used to evaluate the techniques can also be used by others to further compare their techniques to the ones described here.

In the United States, new laws and regulations in several states require increasing percentages of vehicles produced in the future to be zero emission to address climate-related issues. Manufacturers are producing more Electric Vehicles (EVs), but potential customers are hesitant to adopt EVs due to range anxiety. Log truck owners are particularly hesitant to invest in electric log trucks (ELTs) due to forest harvest operations remote nature. However, regenerative braking utilizing gravitational potential energy provides the opportunity to increase the range of ELTs. This manuscript presents the workflow for calculating and mapping energy transportation cost on an ELT using a GIS-enabled tool and demonstrates the tool's applicability through a case study. The study area, the McDonald Dunn Research Forest, included 5,607 ha of forest stands partitioned into 357 harvest polygons averaging 15.7 ha, 326 harvest landings and 295 km of road. Using remotely sensed data from the study site, the tool digitalizes the wood supply chain and optimizes routing based on minimum energy expenditure, providing results such as trip energy cost, distance, and time. The results show the tools forest operations planning potential, applicability as a GIS navigation system, and provides EV buyers with a tool to make informed decisions when investing in technology that could combat climate-related issues. EV adoption will reduce reliance on fossil fuels and potentially ameliorate other environmental problems. [ABSTRACT FROM AUTHOR]

Transportation of forest biomass on steep terrain involves logistical challenges. Trucks with large single trailers are often unable to travel on forest roads due to their narrowness, tight curves, adverse grades and limited areas to turn around. A shorter trailer must be used but then transportation capacity is limited by the trailer volume due to the low bulk density of the processed biomass, particularly when the biomass is dry. With double trailers, transportation capacity can be limited by allowable legal weight based on axle number and spacing. We developed a simulation model that explores the economic feasibility of using double-trailer configurations to transport forest biomass to a bioenergy facility from the grinder at a landing or from a centralized yard in Washington, Oregon and California. Results show that double trailers can be a cost effective alternative to single trailers under limited conditions in Oregon and Washington, but they are not a competitive option in California due to the state's transportation regulations.

Western juniper (Juniperus occidentalis Hook.) is a native species west of the Rocky Mountains that has become noxious as its area increased ten times in the last 140 years. Restoration of the landscapes affected by the spread of juniper through harvesting poses several challenges related to the sparse spatial distribution (trees per hectare) of the resource. Therefore, the objective of the present study is to develop a harvest scheduling strategy that converts the western juniper from a noxious species to a timber resource. We propose a procedure that aggregates individual trees into elementary harvest units by considering the location of each tree. Using the coordinates of each harvest unit and its corresponding landing, we developed a spatially explicit algorithm that aims at the maximization of net revenue from juniper harvest. We applied the proposed landscape restoration approach to two areas of similar size and geomorphology. We implemented the restoration algorithm using two heuristics: simulated annealing and record-to-record travel. To account for the closeness to the mill, we considered two prices at the landing for the juniper: 45 USD/ton and 65 USD/ton. Our results suggest that restoration is possible at higher prices, but it is economically infeasible when prices are low. Simulated annealing outperformed record-to-record travel in both study areas and for both prices. Our approach and formulation to the restoration of landscapes invaded by western juniper could be applied to similar instances where complex stand structures preclude the use of traditional forest stand-level harvest scheduling and require a more granular approach. [ABSTRACT FROM AUTHOR]

Dynamic prices and markets create value for contractors who can readily evaluate the gross and net income differences for alternative merchandizing systems. The majority of the southern U.S.A. relies on tree-length merchandizing, with occasional identification and merchandizing of logs for a specific market or specific tree dimensions or qualities. Cut-to-length (CTL) merchandizing has generated more value when compared to tree-length (TL) marketing, but these comparisons have been limited to specific stands and markets (specifications and prices). The study objective was to demonstrate a process for evaluating cut-to-length and tree-length merchandizing systems in their production of gross value by applying a dynamic programming stem-level optimum bucking approach that maximizes the stem value given specific market conditions. TL merchandizing resulted in a better volume recovery for both regions, but the value recovery was better for CTL merchandizing. Observing the value recovery by diameter class, DSH classes of up to 100 mm had a similar value in both merchandizing systems, but CTL merchandizing yielded a greater or similar value per cubic meter across the range for larger tree sizes. Access to tree data and merchandizing tools needs to be addressed so wood suppliers and landowners may benefit from stem optimization and sensor technology being embedded into modern harvesters and processors. [ABSTRACT FROM AUTHOR]

We model a principal-firm offering training to its agent-worker under two alternative organizational structures: integration, where the principal retains authority to overrule the investment project recommended by the worker; and delegation, where the principal cannot overrule the worker's preferred investment project. We assume that training reduces the worker's effort cost of assembling information about alternative projects' payoffs and identify the conditions under which delegation increases the profit-maximizing intensity of training. Empirical estimates from matched employer-employee data show that workplaces delegating authority do provide more worker training. This result persists in two cross sections, in panel fixed-effect estimates and, critically, in an instrumental variable exercise that also controls for establishment fixed effects. (JEL D21.D22, D23, M53, M54), I. INTRODUCTION Delegation of decision-making allows employers to capture the superior knowledge and information of workers. The objective functions of workers, however, may differ sharply from those of their employers. [...]

The need for improving the cost effectiveness of forest harvest residue utilization for bioenergy production has been widely recognized. A number of studies show that reducing residue moisture content presents advantages for transportation and energy content. However, previous research has not focused on the relative advantages of in-forest drying depending on the residue characteristics from different logging systems, comminution, and equipment mobilization. Residue drying curves were developed using finite element analysis for two primary Pacific Northwest logging systems. These curves were applied to a case study in Oregon in which mixed integer mathematical programming was used to optimize residue delivery to a hypothetical co-generation plant with a generating capacity of 6 megawatt-hours (MWh). Assuming that rear-steered trailers can access cable logging units, approximately 98% of the harvest residue generated by cable logging was delivered to the plant, compared with only 56% of residue generated with a ground-based system, mainly because collection costs incurred with ground-based system residues exceed cost benefits of drier material. By considering the energy content of drier residues, the amount of oven-dried metric tonnes (ODMT) needed to supply the plant can be reduced by 16% without affecting the energy output over a 24-month planning horizon. Lower ODMT demand and shifting to drier material decreases the overall production cost by 20.4%. Key words: harvest residues, moisture content, logging system, co-generation, drying. La necessite d'ameliorer la rentabilite de l'utilisation des residus forestiers pour la production de bioenergie est maintenant largement reconnue. Plusieurs etudes demontrent que la reduction de la teneur en humidite des residus est avantageuse pour le transport et le contenu energetique. Cependant, a ce jour les recherches n'ont pas mis l'accent sur les avantages relatifs du sechage des residus directement en foret, et ce en fonction des caracteristiques des residus selon le systeme de recolte, la comminution des dechets et l'equipement utilise. Des courbes de sechage des residus ont ete developpees en utilisant l'analyse des elements finis pour deux systemes de recolte primaire dans la region du Pacific Northwest. Ces courbes ont ete utilisees dans une etude de cas en Oregon ou une programmation mathematique mixte par nombres entiers a permis d'optimiser la livraison des residus a une usine de cogeneration hypothetique d'une capacite de 6 MWh. En assumant qu'une remorque a direction arriere puisse acceder aux sites de debardage par cable, pres de 98 % des residus generes lors de la coupe par systeme de cablage ont ete livres a l'usine comparativement a seulement 56 % des residus generes avec un systeme au sol. Ceci est principalement du au fait que le cout de la collecte des residus encouru dans le cas du systeme de recolte au sol est plus eleve que celui du materiel plus sec. Etant donne le contenu energetique des residus plus secs, le nombre de tonnes metriques de matieres seches (TMMS) necessaire pour approvisionner l'usine peut etre reduit de 16 % sans affecter la production d'energie sur une periode de 24 mois. La diminution de la demande de TMMS et l'utilisation de materiel plus sec diminuent le cout de production total de 20,4 %. [Traduit par la Redaction] Mots-cles: recolte des residus, teneur en humidite, systeme de recolte, cogeneration, sechage., 1. Introduction After passage of the Energy Independence and Security Act of 2007, several initiatives were developed to improve the efficiency and economics of using forest harvest residues to produce [...]

The moisture content in forest harvest residues is a key factor affecting the supply cost for bioenergy production. Fresh harvest residues tend to contain higher amounts of water, thus making transportation inefficient. Additionally, fresh harvest residues contain greater amounts of needles and bark that may reduce the polysaccharide content, thus affecting the production of liquid fuels derived from cellulosic components. In this study, we estimated the downstream economic effect in the supply chain of collecting, grinding, transporting and pretreating fresh versus aged residues. Specifically, we analyzed the effect of feedstock moisture content on grinder fuel consumption, bulk density, bark and needle content, and polysaccharide proportion. Fresh forest harvest residues were 60% moisture content (wet basis) and aged forest residues were 15% moisture content. The bark and needle proportion is 6.1% higher in fresh residue than in aged residue. Polysaccharides were 26% higher in aged residue than in fresh residue. On a dry-tonne basis, the cost of grinding fresh residues was about the same as that of aged residues. However, considering the difference in bulk density on transportation cost and the difference in polysaccharide yield, the value gain for in-field drying ranges from US$29.60 to US$74.90 per ovendry tonne. Key words: biofuels, bulk density, transportation, economics, moisture content. La teneur en humidite des residus de la recolte forestiere est un facteur cle qui influence le cout d'approvisionnement pour la production de bioenergie. Les residus de coupe frais ont tendance a contenir des quantites plus elevees d'eau ce qui rend leur transport inefficace. De plus, les residus de coupe frais contiennent de plus grandes quantites d'aiguilles et d'ecorce qui peuvent reduire le contenu en polysaccharides et avoir par consequent un impact negatif sur la production de combustibles liquides derives des composantes cellulosiques. Dans cette etude, nous avons evalue l'effet economique en aval dans la chaine d'approvisionnement lie a la collecte, au dechiquetage, au transport et au pretraitement de residus frais comparativement a des residus vieillis. De facon plus precise, nous avons analyse l'effet de la teneur en humidite sur la consommation de carburant de la dechiqueteuse, la densite apparente, le contenu en aiguilles et ecorce et la proportion de polysaccharides. Les residus de coupe frais contenaient 60 % d'humidite (sur la base de la masse humide) alors que les residus vieillis contenaient 15 % d'humidite. La proportion d'aiguilles et d'ecorce etait 6,1 % plus elevee dans les residus frais comparativement aux residus vieillis. Il y avait 26 % plus de polysaccharides dans les residus vieillis comparativement aux residus frais. Sur la base d'une tonne anhydre, le cout relie au dechiquetage des residus frais etait a peu pres le meme que pour les residus vieillis. Cependant, en tenant compte de la difference de densite apparente sur le cout de transport et de la difference de rendement en polysaccharides, la valeur du gain variait de $US29,60 a $US74,90 par tonne anhydre. [Traduit par la Redaction] Mots-cles: biocarburants, densite apparente, transport, economie, teneur en humidite., Introduction High moisture content in forest harvest residues can increase the costs of processing and transportation and may be associated with a reduction in the content of polysaccharides for liquid [...]