Search

Forest biomass harvest has the potential to provide feedstocks for energy production to offset fossil fuel consumption. However, concerns have been raised regarding the ecological sustainability of removing additional biomass from forests, in particular the impacts on biodiversity. In this paper, we used a suite of ground-dwelling arthropod taxa (ground beetles, spiders, and rove beetles) to measure community compositional changes along a gradient of biomass removal treatments 7 years postharvest, and compared against reference. Based on multivariate regression trees, changes in species composition reflected the intensity gradient of the biomass removal treatments or stand attributes associated with the level of forest floor disturbance across all arthropod groups. For each arthropod group, changes in composition were defined primarily by reductions or loss of abundant forest associated species and increases in the number and abundance of species associated with more xeric conditions and increased disturbance intensity. There were no differences between full-tree and tree-length treatments. Overall, results indicated a strong arthropod response to the removal of overstory, forest floor disturbance, and reductions in understory cover mostly resulting from the glyphosate applications. Arthropod recovery would benefit from overstory retention, reduction in forest floor disturbance, and judicious use of glyphosate. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There are two broad approaches to the discrete optimization problem of harvest scheduling with adjacency constraints: the unit-restricted model and the area-restricted model. In this paper two formulations of the area-restricted model are solved using the branch and bound algorithm. These formulations are tested on a set of approximately 30 tactical planning problems that range in size from 346 to 6093 polygons scheduled over three time periods. Our results show that these formulations can be used to solve small- and medium-sized harvest-scheduling problems optimally, or near-optimally, within reasonable periods of computing time. Solution quality and computing time were found to be sensitive to the initial age-class distribution of the forest and the mean polygon size relative to the maximum opening size. In addition, computation of the opening size constraints was found to be very sensitive to the maximum number of polygons in an opening constraint.Il existe deux grandes approches pour résoudre un problème d'optimisation discrète de calendrier de récolte avec des contraintes d'adjacence : le modèle avec superficies prédéterminées et le modèle avec superficies formées dynamiquement. Dans cet article, deux formulations du modèle avec superficies formées dynamiquement sont résolues à l'aide d'une méthode arborescente. Ces formulations sont testées sur un ensemble d'environ 30 problèmes de pla ni fication tactique variant en taille de 346 à 6093 polygones, prévus sur trois périodes. Les résultats montrent que ces formulations peuvent être utilisées pour résoudre de façon optimale ou quasi optimale et avec un temps de calcul raisonnable des problèmes d'ordonnancement de petite et de moyenne taille. On a observé que la qualité de la solution ainsi que le temps de calcul étaient sensibles à la distribution initiale des classes d'age de la forêt et à la taille moyenne des polygones en relation avec la taille maximale des aires de coupe. De plus, le calcul des contraintes de taille des aires de coupe était très sensible au nombre maximum de polygones pouvant être contenu dans une contrainte d'aire de coupe.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The natural disturbance-based management (NDBM) aims to maintain specific structural and compositional attributes of natural forests in managed stands. Operationally, NDBM relies on diversifying and adapting silvicultural practices, including partial harvesting (PC), to expand the range of options beyond that of simply clearcuts (CC). Established in 1998, the Sylviculture et Aménagement Forestier Écosystémique (SAFE) project evaluates this potential in hardwood, mixedwood, and coniferous stands in northwestern Québec, Canada. Our results confirmed a part of the NDBM objectives, i.e., PC allowed the maintenance of stands with mixed structure and composition, constituting an interesting complement to CC, which reset stand regeneration. However, PC did not accelerate the stand transition to later stages with less intensive harvesting or to earlier stages with more intensive harvesting. We essentially had an initial impact, delaying or stopping the stand evolution that dissipates over time and more quickly with less intensive harvesting. Furthermore, our results did not support the ability of PC to enhance the development of old-growth attributes like deadwood. Despite the 20-year horizon of this study, further field surveys will be required in the future to better understand the impact of different silvicultural treatments on forest productivity and biodiversity preservation throughout a forest rotation. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article provides information on a study which examined whether species' shade tolerance regulate natural regeneration abundance and composition when partial harvestings are operated on a landscape scale. Topics discussed include how growth and mortality of natural regeneration influenced by partial harvestings over a 15-year period since harvesting, and difference between randomly selected unharvested control plots and partially harvested plots prior to the harvesting application.

The article provides information on a study which examined the harvesting decisions considering a forest with spruce budworm (SBW) outbreak using a linear multistage stochastic programming model. Topics discussed include impact of insect outbreaks on the forest, approaches to reduce the negative impacts of insect outbreaks, and mitigation strategies for how to best salvage an SBW-infested area using real data in a case study.

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sugar maple decline in eastern North America is caused by a complex combination of factors, with soil nutrition being one of several important determinants. Given the complexity of sugar maple population dynamics and the geographic extent of the species, we support Bailey et al.'s (2019, Can. J. For. Res. 49(7), doi:10.1139/cjfr-2018-0207) argument to interpret results from Cleavitt et al. (2018, Can. J. For. Res. 48(1): 23-31, doi:10.1139/cjfr-2017-0233) with due caution. The experiment at Hubbard Brook Experimental Forest represents an atypical application of contemporary forest practice in the White Mountain National Forest; however, some comments in Bailey et al. (2019) missed the point; others inaccurately characterized our paper. Cleavitt et al.'s (2018) 30-year record of vegetation recovery following whole-tree harvest documented a worrisome inability of a sugar maple population that successfully established after harvest to maintain its position in the understory. This lack of persistence on base-poor soils such as those in the mid and upper elevations of Hubbard Brook Experimental Forest suggests that the successful recruitment of sugar maple is not guaranteed. Key words: forest recovery, northern hardwood forest, whole-tree harvest, sustainable management, community assembly. Le deperissement de l'erable a sucre dans l'est de lAmerique du Nord est cause par une combinaison complexe de plusieurs facteurs importants incluant la nutrition du sol. Etant donne la complexite de la dynamique de population de l'erable a sucre et l'etendue geographique de l'espece, nous soutenons l'argument de Bailey et al. (2019, Can. J. For. Res. 49(7), doi:10.1139/ cjfr-2018-0207) voulant qu'on interprete les resultats de Cleavitt et al. (2018, Can. J. For. Res. 48(1): 23-31, doi:10.1139/cjfr-2017-0233) avec une certaine prudence. L'experience realisee a la foret experimentale de Hubbard Brook constitue une application atypique de la pratique actuelle en foresterie dans la foret nationale des montagnes Blanches; cependant, certains commentaires dans l'article de Bailey et al. (2019) passent a cote du sujet; d'autres caracterisent d'une maniere inexacte notre article. Les donnees de Cleavitt et al. (2018) concernant la recuperation de la vegetation sur une periode de 30 ans a la suite d'une recolte par arbres entiers documentent l'incapacite inquietante d'une population d'erable a sucre, qui a reussi a s'etablir apres la recolte, a maintenir sa position en sous-etage. Ce manque de persistance sur les sols deficients en bases, comme ceux qu'on retrouve a moyenne et haute altitudes a la foret experimentale de Hubbard Brook, indique que le succes du recrutement de l'erable a sucre n'est pas certain. [Traduit par la Redaction] Mots-cles : recuperation de la foret, foret de feuillus nordiques, recolte par arbres entiers, amenagement durable, assemblee communautaire., Introduction The sustainability of sugar maple (Acer saccharum Marsh.) trees in the forests of eastern North America is a major concern (Horsley et al. 2002). Thus, we acknowledge the comments [...]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ecological values are an important aspect of sustainable forest management, but little attention has been paid to maintaining these values when using traditional linear programming (LP) forest management planning models in uncertain planning environments. We embedded an LP planning model that specifies when and how much to harvest in a simulation model of a 'managed' flammable forest landscape. The simulation model was used to evaluate two strategies for dealing with fire-related uncertainty when managing mature and old forest areas. The two seral stage areas were constrained in the LP planning model to a minimum of 10% of the total forest area and the strategies were evaluated under four representative fire regimes. We also developed a risk analysis tool that can be used by forest managers that wish to incorporate fire-related uncertainty in their decision-making. We found that use of the LP model would reduce the areas of the mature and old forest to their lower bound and fire would further reduce the seral areas below those levels, particularly when the mean annual burn fraction exceeds 0.45% per annum. Increasing the minimum area required (i.e., the right-hand side of the constraint) would increase the likelihood of satisfying the minimum area requirements. Les valeurs écologiques constituent un aspect important de l'aménagement forestier durable mais peu d'attention a été accordée au maintien de ces valeurs lorsqu'on utilise des modèles traditionnels de programmation linéaire (PL) pour planifier l'aménagement forestier dans des environnements de planification incertains. Nous avons intégré un modèle de planification par PL qui spécifie quand et quelle quantité il faut récolter dans un modèle de simulation d'un paysage forestier inflammable sous aménagement. Le modèle de simulation a été utilisé pour évaluer deux stratégies qui prennent en charge l'incertitude reliée au feu lorsqu'on aménage des zones de forêt mûre et de forêt surannée. Nous avons introduit une contrainte dans le modèle de planification par PL de telle sorte que les deux stades de succession occupent au moins 10 % de la superficie totale de la forêt et les stratégies ont été évaluées pour quatre régimes de feu représentatifs. Nous avons aussi développé un outil d'analyse du risque d'incendie qui peut être utilisé par les aménagistes forestiers qui souhaitent intégrer l'incertitude reliée au feu dans le processus de prise de décision. Nous avons trouvé que le modèle de PL réduirait les superficies de forêt mature et de forêt surannée à leur limite inférieure et que le feu réduirait la superficie de ces stades de succession sous ces niveaux, particulièrement lorsque la superficie annuelle moyenne brûlée dépasse 0,45 %. Augmenter la superficie minimum exigée (c.-à-d. le côté droit de la contrainte) augmenterait les chances de satisfaire les exigences de superficie minimum. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quantification of stand and forest C stocks in response to different disturbances is necessary to develop climate change mitigation strategies and to evaluate forest C accounting tools. Live tree, dead tree, woody debris (WD), stump, buried wood, and organic and mineral soil C stocks are described in chronosequences of black spruce (Picea mariana (Mill.) BSP) (harvest and fire origin) and balsam fir (Abies balsamea (L.) Mill.) (insect and harvest origin). The largest C stocks were found in mineral soil (≤179 Mg·ha-1), organic soil (≤123 Mg·ha-1), and live tree (≤93 Mg·ha-1) pools. Live tree C changed predictably with disturbance history and time since disturbance, increasing with forest age. Regeneration growth slowed under snags. Thinning accelerated production of larger trees but reduced site live tree C. Dead tree and WD C were temporally dynamic and strongly influenced by disturbance history and time since disturbance, but abundances in differently disturbed forests converged at low levels 40-60 years after disturbance. Only immediately following natural disturbances were there large amounts of snag C (26-30 Mg·ha-1). WD C was relatively abundant <3 years after harvesting (15-17 Mg·ha-1) and 31-36 years after natural disturbance (9 Mg·ha-1). Buried wood stocks were small, but comparable with WD stocks in some forests. Il est nécessaire de quantifier les stocks de C dans les peuplements et les forêts en réaction aux différentes perturbations pour élaborer des stratégies visant à atténuer les effets des changements climatiques et pour évaluer les outils qui servent à mesurer le C des forêts. Les stocks de C dans les arbres vivants, les arbres morts, les débris ligneux (DL), les souches, le bois enfoui, le sol organique et le sol minéral sont décrits dans des chronoséquences d'épinette noire (Picea mariana (Mill.) BSP), issues de coupes et de feux, et des chronoséquences de sapin baumier (Abies balsamea (L.) Mill.) issues de coupes et d'épidémies d'insectes. Le sol minéral (≤179 Mg·ha-1), le sol organique (≤123 Mg·ha-1) et les arbres vivants (≤93 Mg·ha-1) contenaient les plus grandes quantités de C. Le C des arbres vivants variait de façon prévisible en fonction de la nature des perturbations et du temps écoulé depuis qu'est survenue une perturbation et il augmentait avec l'âge de la forêt. La croissance de la régénération ralentissait sous les chicots. L'éclaircie accélérait la production de plus gros arbres mais réduisait le C chez les arbres vivants qui restaient. Le C des arbres morts et des DL était temporairement dynamique et fortement influencé par la nature des perturbations et le temps écoulé depuis qu'est survenue une perturbation, mais l'abondance dans des forêts ayant subi différentes perturbations convergeait vers un faible niveau 40-60 ans après la perturbation. La quantité de C dans les chicots (26-30 Mg·ha-1) était élevée mais seulement immédiatement après une perturbation. Le C était relativement abondant dans les DL moins de 3 ans après une coupe (15-17 Mg·ha-1) et 31-36 ans après une perturbation naturelle (9 Mg·ha-1). La quantité de C dans le bois enfoui était faible mais comparable à la quantité de C dans les DL dans certaines forêts. [ABSTRACT FROM AUTHOR]

We explore how forest resource managers can respond to a potential outbreak of mountain pine beetle (Dendroctonus ponderosae Hopkins, 1902) by assessing how well different forest management strategies achieve various management objectives over time. Strategies include targeting at-risk stands as well as increasing harvest levels. Outcomes are evaluated on the basis of volume flows, net revenues, and the age class structure of the ending inventory. We use a spatially and temporally explicit model to simulate forest management outcomes and consider two different scenarios, one in which the attack occurs early and one where it is delayed. The model utilizes a planning with recourse approach in which the firm can reevaluate its harvesting schedule following the attack. We use company data from west-central Alberta for a 40-year planning exercise. The timing of the attack resulted in small differences in timber supply. However, most strategies performed better financially under an early attack, which limits the harvest of marginal stands. Increasing harvest levels performed better in economic terms but resulted in a very young growing stock with little old forest. The success of any strategy is linked to the timing of the attack and how it affects the growing stock, subsequently impacting timber and revenue flows. Nous examinons de quelle façon les gestionnaires des ressources pourraient réagir à une épidémie du dendroctone du pin ponderosa (Dendroctonus ponderosae Hopkins, 1902) en évaluant dans quelle mesure différentes stratégies d’aménagement forestier permettent d’atteindre différents objectifs d’aménagement avec le temps. Parmi les stratégies qui sont évaluées, on peut cibler les peuplements à risque aussi bien qu’augmenter le volume de récolte. Les résultats sont évalués sur la base des flux de volume, des revenus nets et de la structure des classes d’âge du stock final. Nous utilisons un modèle explicite dans le temps et l’espace pour simuler les résultats de l’aménagement forestier et examiner deux scénarios différents : un scénario selon lequel l’attaque survient tôt et l’autre selon lequel elle est retardée. Le modèle utilise une planification avec une approche de recours qui permet à l’entreprise de réévaluer son calendrier de coupe à la suite d’une attaque. Nous utilisons des données de compagnies du centre ouest de l’Alberta pour un exercice de planification de 40 ans. Le moment de l’attaque a entraîné de petites différences dans les stocks de bois. Cependant, la plupart des stratégies ont mieux performé financièrement dans le cas d’une attaque hâtive qui limite la récolte des peuplements marginaux. L’augmentation du volume de récolte a mieux performé du point de vue économique mais a laissé un matériel sur pied très jeune et peu de vieilles forêts. Peu importe la stratégie, son succès est lié au moment de l’attaque et à la façon dont elle affecte le matériel sur pied, ce qui a subséquemment un impact sur les flux de bois et de revenus. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The economic decision model serving as an objective function in forest economics was conceived originally by Faustmann at the stand level. Nevertheless, the tree level seems to be an appropriate scale for analysis, especially for harvesting decisions and certain estimations both at tree and stand levels. However, the Faustmann formula cannot be directly applied to the tree level. The present research has provided certain tree-level formulations of the Faustmann formula, including, in particular, tree expectation value (TEV) and land expectation value (LEV). TEV and tree-level LEV formulas were developed by analyzing the Faustmann formula under deterministic conditions. Unlike previous tree-level decision models presented in the forest economics literature, TEV and tree-level LEV formulas incorporate the expectation value of the land occupied by trees and its variability over time as well as the interaction between trees and their trajectories (cutting age). The proposed formulas were then compared with the Faustmann formula using the first-order condition of optimal harvest age. The TEV and tree-level LEV formulas appeared to be absolutely compatible with the Faustmann formula. The utility of the proposed formulas was then illustrated with application examples, including target diameter, stand expectation value, TEV, LEV, and the value of damage to beech trees or stands in northeastern France. Le modèle de décision économique qui sert de fonction objective en économie forestière a initialement été conçu par Faustmann à l’échelle du peuplement. Néanmoins, l’arbre semble être un niveau d’analyse approprié, spécialement pour les décisions relatives à la récolte et pour certaines estimations, tant à l’échelle de l’arbre que du peuplement. Cependant, la formule de Faustmann ne peut pas être directement appliquée à l’échelle de l’arbre. La présente recherche a fourni certaines formulations de la formule de Faustmann à l’échelle de l’arbre, incluant plus particulièrement la valeur d’attente de l’arbre (VAA) et la valeur d’attente du fond (VAF). Les formules de la VAA et de la VAF à l’échelle de l’arbre ont été développées en analysant la formule de Faustmann sous des conditions déterministes. Contrairement aux différents modèles de décisions à l’échelle de l’arbre décrits dans la littérature, les formules de la VAA et de la VAF à l’échelle de l’arbre incluent la valeur d’attente du fond occupé par les arbres et sa variabilité au fil du temps, de même que l’interaction entre les arbres et leur évolution (âge de récolte). Les formules proposées ont ensuite été comparées à la formule de Faustmann en utilisant la condition de premier ordre de l’âge optimal de la récolte. Les formules de la VAA et de la VAF à l’échelle de l’arbre semblent tout à fait compatibles avec la formule de Faustmann. L’utilité des formules proposées a ensuite été démontrée par des exemples d’application incluant le diamètre cible, la valeur d’attente du peuplement (VAP), la VAA, la VAF et la valeur des dommages aux arbres et aux peuplements de hêtre du nord-est de la France. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Using inventory data from a long-term silviculture experiment in east-central Maine, spatial models were developed to analyze 28 years (1974–2002) of stand structural dynamics. Differences in spatial pattern, species mingling, height differentiation, and relative stand complexity index (rSCI) were compared among five treatments: commercial clear-cutting, fixed diameter-limit, 5 year single-tree selection, three-stage shelterwood (both with and without precommercial thinning), and unharvested natural areas. Regardless of treatment, regeneration events (whether induced by natural breakup of the overstory or by harvesting) increased aggregation in spatial pattern and reduced species mingling, more so in the commercial clearcut and fixed diameter-limit treatments where hardwood densities were highest. Regular spatial patterns were rare. Height differentiation values for individual trees and stand-level mean rSCI were generally highest in untreated natural areas and 5 year selection treatments, intermediate in commercial clearcut and fixed diameter-limit treatments, and lowest in three-stage shelterwood treatments. After a brief adjustment period, precommercial thinning in a shelterwood treated stand generally increased species mingling, height differentiation, and rSCI. Two untreated natural areas exhibited divergent pathways of structural development. Dynamics in uneven-aged selection treatments more closely resembled that of the untreated natural areas than did the shelterwood, commercial clearcut, or fixed diameter-limit treatments. En utilisant les données d’inventaire d’une expérience sylvicole à long terme dans le centre-est de l’État du Maine, aux tats-Unis, des modèles spatiaux ont été mis au point pour analyser la dynamique de la structure du peuplement pendant une période de 28 ans (1974 à 2002). Les différences de patron spatial, de mélange d’espèces, de différenciation de la hauteur et d’indice relatif de complexité des peuplements (ICPr) ont été comparées parmi cinq traitements : la coupe à blanc commerciale, la coupe à diamètre limite fixe, la coupe de jardinage par pied d’arbre selon une rotation de cinq ans, la coupe progressive d’ensemencement en trois étapes (avec et sans éclaircie commerciale) et des peuplements naturels non coupés. Indépendamment du traitement, l’établissement de la régénération (induit par la sénescence naturelle des arbres dominants ou par la coupe) augmentait l’agrégation des patrons spatiaux et diminuait le mélange des espèces et ce, de façon plus marquée dans la coupe à blanc commerciale et dans la coupe à diamètre limite où la densité des espèces feuillues était la plus forte. Les patrons spatiaux réguliers étaient rares. Les valeurs de différenciation de la hauteur des arbres individuels et d’ICPr moyen à l’échelle du peuplement étaient généralement plus élevées dans les peuplements naturels non traités et dans la coupe de jardinage selon une rotation de 5 ans, intermédiaires dans la coupe à blanc commerciale et dans la coupe à diamètre limite, et plus faibles dans la coupe progressive d’ensemencement en trois étapes. Après une brève période d’ajustement, l’application d’une éclaircie précommerciale dans un peuplement soumis à la coupe progressive augmentait généralement le mélange des espèces, la différenciation de la hauteur et l’ICPr. Deux peuplements naturels non traités montraient des trajectoires divergentes de développement de la structure. La dynamique dans les coupes de jardinage appliquées à des structures inéquiennes était plus près de celle des peuplements naturels non traités que ne l’étaient la coupe progressive d’ensemencement, la coupe à blanc commerciale ou la coupe à diamètre limite fixe. [ABSTRACT FROM AUTHOR]