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Log logistics include sorting, processing, and transporting of logs from their place of harvest to demand locations. These activities account for a significant portion of the total log procurement costs; therefore, attempts were made in previous studies to optimize some aspects of log logistics. However, operational details, such as sorting decisions, truck compatibility requirements, and social objectives, are often disregarded in the optimization literature. Incorporating these details into the model makes the results more realistic and applicable. To address these gaps, a bi-objective mixed-integer programming model is developed in this paper to optimize log logistics. The first objective is to minimize total logistics costs, and the second objective is to provide a balanced workload for trucking contractors. The bi-objective model is solved using the goal programming approach. The model is applied to log logistics of a large Canadian forest company, where trucking contractors use heterogeneous fleet of trucks to carry various log sorts from cutblocks to sort yards for sorting. The planning horizon is 4 weeks with daily decisions. The goal programming model generates balanced workloads for the contractors with less than 0.4% increase in total costs compared to the single objective model where only the total cost is minimized. Key words: log logistics, goal programming, bi-objective optimization, social objective, sorting decisions, compatibility requirements. La logistique des rondins inclut le tri, le traitement et le transport des rondins a partir du lieu de leur recolte jusqu'aux lieux ou il y a une demande. Ces activites representent une partie importante des couts totaux de l'approvisionnement en rondins et, par consequent, des tentatives ont ete faites dans des etudes anterieures pour optimiser certains aspects de la logistique des rondins. Toutefois, les details operationnels, par exemple les decisions de tri, les exigences de compatibilite des camions et les objectifs sociaux, sont souvent ignores dans la documentation sur l'optimisation. L'integration de ces details dans le modele rend les resultats plus realistes et plus applicables. Pour combler ces lacunes, un modele de programmation d'entier relatif mixte bi-criteres d'optimisation est developpe dans la presente communication dans le but d'optimiser la logistique des rondins. Le premier objectif est de minimiser les couts totaux de la logistique et le second objectif est de fournir une charge de travail equilibree aux entrepreneurs en camionnage. Le modele bi-criteres d'optimisation est resolu en utilisant une approche de programmation des objectifs. Le modele est applique a la logistique des rondins d'une importante compagnie forestiere canadienne oU les entrepreneurs en camionnage utilisent une flotte heterogene de camions pour transporter diverses sortes de rondins a partir des blocs de coupe jusqu'aux parcs de triage pour y etre tries. L'horizon de planification est de 4 semaines avec des decisions quotidiennes. Le modele de programmation des objectifs genere des charges de travail equilibrees pour les entrepreneurs avec une augmentation des couts totaux de moins de 0.4 % comparativement au modele a objectif unique oU seulement le cout total est minimise. [Traduit par la Redaction] Mots-cles : logistique des rondins, programmation des objectifs, optimisation bi-criteres, objectif social, decisions de tri, exigences de compatibilite., 1. Introduction Log logistics include sorting, processing, transporting, and storing logs. Overall, these activities make up a large proportion of the total log procurement costs. An important element of log [...]

Forestry is an important component of Canada's economy with British Columbia (BC) contributing almost half to the national roundwood production. Yet, the country's timber supply and forest economy are threatened by climate change, with increased frequency and severity of natural disturbances and changes in forest productivity. Mountain pine beetle (Dendroctonus ponderosae) outbreaks are endemic in BC, but the latest climate change-driven outbreak has resulted in a cumulative loss of over half of all merchantable pine, leading to a mid-term timber supply shortage. In this study, we investigate the potential of commercial thinning and alternative planting regimes based on species diversification and assisted species migration to mitigate the anticipated decrease in timber supply in BC. We simulated the long-term effects of these management options in a case study area in interior BC, using a toolbox that combines management- and research-oriented data and models. We found that combining commercial thinning and species diversification has the best potential to mitigate future timber supply shortages in BC. We discuss the limits of this toolbox approach and identify research needs and recommendations for future studies aiming at modelling cumulative effects of management, climate change, and natural disturbances on timber supply. [ABSTRACT FROM AUTHOR]

Forests provide countless ecological, societal, and climatological benefits. With changing climate, maintaining certain services may lead to a decrease in the quantity or quality of other services available from that source. Accordingly, our research objective is to analyze the effects of the provision of a certain ecosystem service on the economically optimized harvest schedules and how harvest schedules will be influenced by climate change. Based on financial portfolio theory, we determined, for two case study regions in Austria and Slovakia, treatment schedules based on nonlinear programming, which integrates climate- sensitive biophysical risks and risk-averting behavior of the management. In both cases, results recommend reducing the overaged stocking volume within several decades to establish new ingrowth, leading to an overall reduction of age and related risk, as well as an increase in growth. Under climate change conditions, the admixing of hardwoods towards spruce-fir-beech (Austria) or spruce-pine-beech (Slovakia) stands should be emphasized to account for the changing risk and growth conditions. Moreover, climate change scenarios either increased (Austria) or decreased (Slovakia) the economic return slightly. In both cases, the costs for providing the ecosystem service 'rock fall protection' increases under climate change. Although in the Austrian case there is no clear tendency between the management options, in the Slovakian case, a close-to-nature management option is preferred under climate change conditions. Increasing tree species richness, increasing structural diversity, replacing high-risk stands, and reducing average growing stocks are important preconditions for a successful sustainable management of European mountain forests in the long term. Key words: forest management, ecosystem services, climate change, economic optimization, risk integration, management planning. Les forets procurent d'innombrables benefices ecologiques, societaux et climatologiques. A cause des changements climatiques, le maintien de certains services pourrait entrainer une baisse de la qualite ou de la quantite d'autres services provenant de la meme source. Par consequent, l'objectif de nos travaux de recherche consiste a analyser comment le fait de procurer un certain service de l'ecosysteme affecte les calendriers de recolte optimises sur le plan economique et de quelle facon les calendriers de recolte seront influences par les changements climatiques. En se basant sur la theorie moderne du portefeuille nous avons, pour deux regions servant d'etude de cas, l'Autriche et la Slovaquie, elabore des calendriers de traitement sur la base de la programmation non lineaire en integrant les risques biophysiques sensibles au climat et le comportement de gestion visant a minimiser les risques. Les resultats recommandent dans les deux cas de reduire le volume du materiel sur pied suranne sur plusieurs decennies afin de favoriser l'etablissement de nouvelles recrues entrainant ainsi une reduction globale de l'age et du risque inherent ainsi qu'une augmentation de la croissance. On devrait mettre l'accent sur l'incorporation de feuillus pour evoluer vers des peuplements d'epicea, sapin et hetre (Autriche) ou d'epicea, pin et hetre (Slovaquie) afin de tenir compte des risques et des conditions de croissance qui sont modifies a cause des changements climatiques. De plus, les scenarios de changement climatique augmentent (Autriche) ou reduisent (Slovaquie) legerement la rentabilite economique. Dans les deux cas, les couts associes a la protection contre l'effondrement des services de l'ecosysteme augmentent avec les changements climatiques. Tandis que dans le cas de l'Autriche il n'y a pas de tendance claire parmi les options d'amenagement visant a faire face aux changements climatiques, une option d'amenagement ecosystemique est preferee dans le cas de la Slovaquie. Augmenter la richesse en especes d'arbre, augmenter la diversite structurale, remplacer les peuplements a haut risque et rajeunir le materiel sur pied sont d'importantes conditions prealables pour assurer le succes a long terme de l'amenagement durable des forets de montagne en Europe. [Traduit par la Redaction] Mots-cles : amenagement forestier, services de l'ecosysteme, changements climatiques, optimisation economique, integration du risque, planification de l'amenagement., 1. Introduction Twenty-nine percent of the European Union's (EU27) land surface is covered by mountains (European Environment Agency (EEA) 2010), and forests cover 41% of this mountainous area, where they [...]

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The competitiveness of forest companies is strongly affected by the costs associated with getting the raw material to the mills. As harvesting costs contribute significantly to this cost, mathematical programming models were developed to optimize the scheduling of harvest activities within and between cut blocks to reduce the overall cost. However, the precedence relationship between harvesting activities occurring concurrently across multiple cut blocks has not been considered in the existing literature. In this paper, a mixed-integer linear programming model is developed to optimize the scheduling of harvesting activities, considering the precedence relationship among harvesting activities. The objective of the model is to minimize the total costs. The model determines the start time and end time of each harvesting activity at each cut block, considering the movement time of machines between cut blocks. The model is applied to the case of a large forest company in British Columbia, Canada. The model's harvesting cost is only 1.37% higher than the lowest possible harvesting cost, and only 3 assigned machines have an idle time. The detailed harvesting schedule is generated based on the start time, the end time, and the operating time for each activity at each cut block. [ABSTRACT FROM AUTHOR]

Stand structure is a key attribute of forest ecosystems. Mixed-tree plantations are widely felt to be the appropriate option for providing a broad range of goods and environmental services and to reduce susceptibility to natural hazards. However, the debate continues whether mixed plantations can achieve greater financial return than monocultures can. In this study, mixed-species stands of conifers and hardwood species were analyzed in consideration of economically relevant factors. Growth performance and resistance to hazards and pests are widely noted in the literature and are of general economic interest. Thus meta-analyses of relevant studies were conducted to test the following hypotheses: (1) mixing tree species has no significant influence on growth performance or resistance against hazards and pests and, if refuted, (2) mixing tree species causes mainly negative effects on growth performance and resistance against hazards and pests. However, a positive impact of mixing tree species was proven for resistance against windthrow and pests. The meta-analysis on growth performance just as well indicates a positive effect of mixing tree species. Overall, these positive results underscore the need for a large number of additional studies to examine different silvicultural systems to develop optimal management prescriptions to benefit from positive interactions. La structure du peuplement est un attribut cle des ecosystemes forestiers. Les plantations mixtes sont largement considerees comme une option appropriee pour fournir une large gamme de produits et de services environnementaux ainsi que pour reduire la predisposition aux catastrophes naturelles. Cependant, le debat persiste a savoir si les plantations mixtes peuvent procurer un meilleur rendement financier que les monocultures. Dans cette etude, des peuplements mixtes composes d'especes feuillues et resineuses ont ete analyses en tenant compte de facteurs pertinents du point de vue economique. La croissance et la resistance aux catastrophes et aux ravageurs sont couramment mentionnees dans la litterature et presentent un interet economique general. Des meta-analyses des etudes pertinentes ont par consequent ete realisees pour tester les hy-potheses suivantes: (1) le fait de melanger les especes d'arbre n'a aucun effet significatif sur la croissance ou la resistance aux catastrophes et aux ravageurs et si cette hypothese est refutee, (2) le fait de melanger les especes d'arbre a surtout des effets negatifs sur la croissance et la resistance aux catastrophes et aux ravageurs. Toutefois, un effet positif du melange des especes a ete demontre dans le cas de la resistance au chablis et aux ravageurs. La meta-analyse indique egalement que le melange des essences a un effet positif sur la croissance. Dans l'ensemble, ces resultats positifs soulignent la necessite d'ef-fectuer un grand nombre d'etudes additionnelles pour examiner differents systemes sylvicoles dans le but d'elaborer des prescriptions d'amenagement optimales pour beneficier des interactions positives. [Traduit par la Redaction], Introduction Until the end of the 18th century, central European deciduous forests were degraded. Although foresters as well as scientists have been discussing whether or not pure or mixed-species stands [...]

Applied educational opportunities in forestry undergraduate curricula are essential for a complete postsecondary degree program. Walking distance to local urban forests present a way to teach forestry students in applied settings, while reducing the time, cost, and travel logistics. A case study at a Canadian university (University of British Columbia) was used to connect urban forest canopy cover to forestry learning objectives and walking time to the main teaching building. Individual tree canopies were identified with light detection and ranging data and aggregated to 0.05 ha grid sections. Using canopy cover and forest arrangement, the urban forest was classified into closed, open, small, sparse, or non- forest classifications. Forestry learning objectives were matched with each forest classification in conjunction with walkability to identify critical local location for forestry education. Results identified key areas suitable for teaching forestry and for linking forestry educational values with easily accessible high value locations. [ABSTRACT FROM AUTHOR]