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Copyright of Environmental Reviews 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 Environmental Reviews 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 boreal zone and its ecosystems provide numerous provisioning, regulating, cultural, and supporting services. Because of its resources and its hydroelectric potential, Canada's boreal zone is important to the country's resource-based economy. The region presently occupied by Canada's boreal zone has experienced dramatic changes during the past 3 million years as the climate cooled and repeated glaciations affected both the biota and the landscape. For about the past 7000 years, climate, fire, insects, diseases, and their interactions have been the most important natural drivers of boreal ecosystem dynamics, including rejuvenation, biogeochemical cycling, maintenance of productivity, and landscape variability. Layered upon natural drivers are changes increasingly caused by people and development and those related to human-caused climate change. Effects of these agents vary spatially and temporally, and, as global population increases, the demands and impacts on ecosystems will likely increase. Understanding how humans directly affect terrestrial and aquatic ecosystems in Canada's boreal zone and how these effects and actions interact with natural disturbance agents is a prerequisite for informed and adaptive decisions about management of natural resources, while maintaining the economy and environment upon which humans depend. This paper reports on the genesis and present condition of the boreal zone and its ecosystems and sets the context for a detailed scientific investigation in subsequent papers published in this journal on several key aspects: carbon in boreal forests; climate change consequences, adaptation, and mitigation; nutrient and elemental cycling; protected areas; status, impacts, and risks of non-native species; factors affecting sustainable timber harvest levels; terrestrial and aquatic biodiversity; and water and wetland resources. [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.)

The Canadian boreal logging industry has attracted little or no attention from economic researchers in spite of its importance for the competitiveness and long-term survival of other forest-based industries. This article uses a panel data set covering the period from 1977 to 1995 to analyze technical efficiency, technical change, and total factor productivity growth in the logging industries for six boreal provinces. The production technology is represented using a data envelopment analysis model. A transitive measure of productivity change that combines technical progress and changes in the degree of productive efficiency is computed. The empirical investigation reveals that logging activities in the boreal region are characterized by substantial efficiency differentials among the regions. Results from a Tobit analysis of efficiency differentials indicate that forest resource characteristics such as forest density and proportion of hardwood production were found to have positive effects. There was also evidence of significant positive scale effects. Engineering construction per area seems to be negatively related to efficiency. Total factor productivity in the boreal logging industry progressed at an average annual rate of 1.56%.L'industrie de la récolte forestière en forêt boréale canadienne a suscité peu ou pas d'intérêt de la part de chercheurs en écon omie et ce malgré son importance pour la compétitivité et la survie à long terme des industries de transformation du bois. Cet article utilise des données en panel couvrant la période de 1977 à 1995 afin d'analyser l'efficience technique, les changements technologiques et le gain global de productivité de l'industrie de la récolte dans six provinces de la zone boréale. La technologie de production est représentée à l'aide d'un modèle d'analyse par enveloppement des données. Une mesure transitive du changement de productivité qui combine le progrès technologique ainsi que les changements dans le niveau d'efficience est présentée. L'approche empirique a révélé que des différences substantielles caractérisaient l'efficience des activités de récolte parmi les régions de la zone boréale. Les résultats d'une analyse Tobit sur les différences d'efficience indiquent que les caractéristiques de la ressource forestière telles que la densité et la proportion des essences feuillues avaient des effets positifs. Des rendements d'échelle positifs ont également été détectés. Les travaux d'ingénierie par superficie traitée semblent affecter négativement l'efficience. La productivité globale dans l'industrie de la récolte en forêt boréale a progressée à un taux annuel moyen de 1,56 %.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Conservation efforts to sustain water resources and aquatic biodiversity in boreal watersheds will require reliable information on the recent status of various indicator species and an improved understanding of the risks to aquatic biodiversity posed by resource development activities. We reviewed the recent state of knowledge on the responses of aquatic biodiversity to forest management, pulp and paper mill effluents, hydroelectric impoundments, mining of minerals and metals, oil sands extractions, and peat mining and offer a prognosis for aquatic biodiversity under each of these environmental stressors. Despite the prevalence of natural resource development in Canada's largest forest ecosystem, there was a limited amount of published literature on the effects of many of the disturbance types on various indicators of aquatic biodiversity, making it difficult to produce a current and reliable status assessment. Across most of the boreal zone, there is a lack of coordinated, consistent data collection for many of the bioindicators and disturbance types discussed in this review. Forecasting the future state of aquatic biodiversity across the boreal zone is challenged by increasing natural resource development and its interactions with other stressors, especially climate change. The cumulative effects of multiple stressors coupled with resource development activities in boreal watersheds remain largely unknown. More importantly, the ecological thresholds for these cumulative effects (that is, the point at which aquatic ecosystems and their biodiversity cannot recover to a desired state within a reasonable time frame) are also unknown and remain gaps in our knowledge. The recent literature identifies a number of risks to aquatic biodiversity at local (tens of square kilometres) to regional (hundreds of square kilometres) scales associated with natural resource development. There are indications that many of these risks can be minimized by 'greener' technologies for resource development and reclamation, practical conservation planning and regulation, and increased stewardship in watershed management, although the effectiveness of many of these measures cannot yet be assessed from the published literature. [ABSTRACT FROM AUTHOR]

Provides information on the 4th International Workshop on Disturbance Dynamics in Boreal Forest held at the University of Northern British Columbia on August 9 to 12, 2002. Issues involving forest management discussed at the event; Keynote speakers who were present in the workshop; Discussion on the importance and role of disturbance in shaping boreal forest.

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 Environmental Reviews 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 Environmental Reviews 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 Environmental Reviews 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 Botany 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 Zoology 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 Botany 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.)

The effects of partial and clear-cut harvesting on forest floor physical, chemical, and biological properties, forest floor mesofauna, and nutrient cycling were investigated in conifer- and deciduous-dominated stands of Alberta's mixedwood boreal forest. Forest floor samples were collected 2.5 years after harvest from clearcuts, strip-cut corridors in a partial cut, green tree retention patches in a partial cut, and uncut control sites. Partial cuts showed intermediate decreases in annual litter input and NH[sub 4] -N between uncut and clear-cut sites of both the deciduous and conifer stands, as did microbial biomass, PO[sub 4] -P, mesofauna abundance (total, Acari, and Collembola), and fine root biomass in the conifer stands. In the deciduous stands, microbial biomass and fine root biomass in partial- and clear-cut treatments were not significantly different, but were significantly reduced compared with the uncut controls. Mesofauna abundance was reduced in the corridors of the partial-cut treatment compared with partial-cut patch, clear-cut, and uncut treatments. In both deciduous and conifer stands, NO[sub 3] -N was elevated in the partial-cut corridors and clearcuts compared with partial-cut patch and uncut treatments. Findings from this study show that negative impact to forest floor properties associated with clear-cut harvesting may be reduced in partial-cut harvesting systems.Les effets de la coupe à blanc et de la coupe partielle sur les propriétés physiques, chimiques et biologiques de la couverture morte, sur la mésofaune de la couverture morte et sur le recyclage des nutriments ont été étudiés dans des peuplements dominés soit par des conifères, soit par des feuillus, dans la forêt mixte boréale de l'Alberta. Des échantillons de la couverture morte ont été prélevés dans des sites coupés à blanc, dans les corridors de coupes partielles par bandes, dans les îlots de réserves de coupes partielles et dans des sites témoins non coupés deux ans et demi après la récolte. La coupe partielle a entraîné une diminution de l'apport annuel de litière et de N (NH[sub 4] ) intermédiaire entre les sites coupés à blanc et les sites non coupés dans les deux types de peuplements de même qu'une diminution de la biomasse microbienne, du P (PO[sub 4] ), de l'abondance de la mésofaune (totale, d'acariens et de collemboles) et de la biomasse des racines fines dans les peuplements résineux. Dans les peuplements feuillus, la biomasse microbienne et la biomasse de racines fines ne différaient pas significativement entre la coupe partielle et la coupe à blanc mais étaient significativement plus faibles que dans les sites témoins non coupés. L'abondance de la mésofaune dans les corridors de la coupe partielle était inférieure à celle observée dans la coupe partielle avec réserves, dans la coupe à blanc et dans les sites non coupés. Tant dans les peuplements résineux que feuillus, N (NO[sub 3] ) était plus élevé dans les corridors de la coupe partielle et dans la coupe à blanc que dans la coupe partielle avec réserves ou dans les sites non coupés. Les résultats de cette étude montrent que l'impact négatif de la coupe à blanc sur les propriétés de la couverture morte peut être minimisé avec des systèmes de coupe partielle.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Discusses how fire history and forest dynamics were reconstructed for a territory located in the south-central boreal forest of Quebec, Canada. How fire cycle was characterized using a random sampling strategy combined with archival data on fires; Consideration of bioclimatic subdomain, land use, surficial deposit, and mean distance; Characterizations of forest dynamics; Findings that species replacement occurs in the eastern boreal forest of Canada.

Old-growth black spruce (Picea mariana) boreal forest in the Clay Belt region of Ontario and Quebec is an open forest with a low canopy, quite different from what many consider to be "old growth". Here, we provide an overview of the characteristics of old-growth black spruce forest for three different site types on organic, clay, and coarse deposits. Our objectives were (1) to identify the extent of older forests; (2) to describe the structure, composition, and diversity in different age classes; and (3) to identify key processes in old-growth black spruce forest. We sampled canopy composition, deadwood abundance, understorey composition, and nonvascular plant species in 91 forest stands along a chronosequence that extended from 20 to more than 250 years after fire. We used a peak in tree basal area, which occurred at 100 years on clay and coarse sites and at 200 years on organic sites, as a process-based means of defining the start of old-growth forest. Old-growth forests are extensive in the Clay Belt, covering 30–50% of the forested landscape. Black spruce was dominant on all organic sites, and in all older stands. Although there were fewer understorey species and none exclusive to old-growth, these forests were structurally diverse and had greater abundance of Sphagnum, epiphytic lichens, and ericaceous species. Paludification, a process characteristic of old-growth forest stands on clay deposits in this region, causes decreases in tree and deadwood abundance. Old-growth black spruce forests, therefore, lack the large trees and snags that are characteristic of other old-growth forests. Small-scale disturbances such as spruce budworm and windthrow are common, creating numerous gaps. Landscape and stand level management strategies could minimize structural changes caused by harvesting, but unmanaged forest in all stages of development must be preserved in order to conserve all the attributes of old-growth black spruce forest. Key words: boreal forest, old growth, paludification, Picea mariana, structural development, succession.Dans la région de la ceinture d'argile de l`Ontario et du Québec, la forêt boréale ancienne d'épinette noire (Picea mariana) est une forêt ouverte, où la canopée est basse, ce qui diffère considérablement de la perception que le public a d'une « forêt ancienne ». Nous présentons ici un aperçu des caractéristiques de la pessière noire ancienne poussant sur dépôts organiques, argileux et grossiers. Nos objectifs étaient: (1) déterminer l'étendue des forêts plus vieilles; (2) décrire la structure, la composition et la diversité en fonction des classes d'âge; (3) mettre en lumière les processus clés dans la pessière noire ancienne. Nous avons échantillonné la composition de l'étage supérieur, l'abondance de bois mort, la composition du sous-bois et les plantes invasculaires de 91 peuplements forestiers, le long d'une chronoséquence de 20 à plus de 250 ans après feu. Nous avons utilizé le maximum de la surface terrière des arbres, observé à 100 ans sur les dépôts argileux et grossiers et à 200 ans sur les dépôts organiques, pour définir le début de la forêt ancienne. Dans la ceinture d'argile, les forêts anciennes sont abondantes, couvrant de 30 à 50 % du paysage forestier. L'épinette noire domine sur tous les sols organiques, ainsi que dans tous les peuplements plus âgés. Bien que les espèces du sous-bois soient moins nombreuses et qu'aucune d'elles ne leur soit exclusivement liée, les forêts anciennes présentent une structure variée et renferment davantage de Sphagnum, de lichens épiphytes et d'éricacées. La paludification, processus caractéristique des peuplements forestiers anciens sur dépôts argileux dans cette région, entraîne une diminution de l'abondance des arbres et du bois mort. Par conséquent, on ne trouve pas dans les forêts anciennes d'épinette noire, les quantités élevées de gros arbres et de chicots qui caractérisent d'autres forêts anciennes. Des perturbations à petite échelle, comme les épidémies de la tordeuse des bourgeons de l'épinette et les chablis, sont fréquentes et créent de nombreuses trouées. Des stratégies d'aménagement à l'échelle du paysage et du peuplement pourraient réduire les changements structuraux causés par la récolte; cependant, il est essentiel de préserver des peuplements non aménagés à tous les stades de développement pour conserver toutes les caractéristiques d'une pessière noire ancienne. Mots clés : forêt boréale, forêt ancienne, paludification, Picea mariana, développement structurale, succession. [Traduit par la rédaction] [ABSTRACT FROM AUTHOR]

Wet boreal forests occur primarily in Atlantic Canada especially in Newfoundland, but examples are also found in Quebec and the northeastern U.S.A. These forests are dominated by balsam fir (Abies balsamea), which is susceptible to fire but flourishes in wetter environments where fire is absent. The major stand disturbances are caused by insects, primarily spruce budworm (Choristoneura fumiferana) and hemlock looper (Lambdina fiscellaria), followed by root rots and blowdown. Stands in Newfoundland were characterized by large amounts of dead standing and fallen wood, as a result of self-thinning processes and insect attacks. A comparison of 40-, 60-, and >= 80-year-old forests in Newfoundland indicated that the oldest stage of balsam fir forests had a distinctly different structure, including more large dead and fallen wood, a more irregular canopy including gaps, a more diverse ground flora, more moss ground cover, a more variable tree height, taller snags, fewer white birch snags, and fewer deciduous small trees. These differences were reflected in various plant and animal faunas that were distinct in the old forest including: flowering plants, beetles, Collembola, oribatid mites, mammals, and birds. Several species of plants and animals were only found in the oldest forest stands, including a high percentage among the arthropods. Suggested indicator species at the stand level include black-backed woodpeckers (Picoides arcticus) and marten (Martes americana). Logging results in a larger mean patch size than that caused by natural insect disturbances, possibly affecting dispersal by soil organisms and plants within the new landscape. A portion of the landscape, keyed to species with the largest area requirements to maintain their populations, including marten, black-backed woodpeckers, and (or) boreal owls (Aegolius funereus) could guide the amount of old forest, and individual patch sizes, required across a landscape over time. Key words: old growth, biodiversity, species richness, forest management, balsam fir.Les forêts boréales humides se trouvent principalement dans les provinces canadiennes de l'Atlantique, surtout à Terre-Neuve. Il en existe également au Québec et dans le Nord-Est des États-Unis. Dans ces forêts domine le sapin baumier (Abies balsamea), sensible au feu, qui prospère dans les milieux plus humides où le feu est absent. Les principales sources de perturbation des peuplements sont les insectes, plus particulièrement la tordeuse des bourgeons de l'épinette (Choristoneura fumiferana) et l'arpenteuse de la pruche ( Lambdina fiscellaria), puis les pourridiés et les chablis. À Terre-Neuve, les peuplements se caractérisent par des quantités importantes d'arbres morts sur pied et de bois au sol résultant des processus d'éclaircie naturelle et des attaques d'insectes. Une comparaison de forêts terre-neuviennes de 40, 60 et 80+ ans a indiqué que, par rapport aux peuplements de 40 ou 60 ans, les sapinières les plus âgées présentent une structure nettement différente, se caractérisant, entre autres, par une plus grande quantité de gros bois morts, un étage supérieur plus irrégulier avec des trouées, une flore au sol plus diversifiée, une strate muscinée plus abondante, une hauteur des arbres plus variable, des chicots de plus grande hauteur, moins de chicots de bouleau à papier et moins de petits arbres feuillus. Ces différences se reflètent dans diverses composantes de la flore et de la faune qui sont distinctes dans la vieille forêt (plantes à fleurs, coléoptères, collemboles, acariens oribates, mammifères et oiseaux, entre autres). Plusieurs espèces végétales et animales, dont un pourcentage élevé d'arthropodes, n'ont été trouvées que dans les peuplements forestiers les plus âgés. Le pic à dos noir (Picoides arcticus) et la martre (Martes americana) sont suggérés en tant qu'espèces indicatrices au niveau du peuplement. La récolte forestière crée des trouées en moyenne plus grandes que celles résultant des perturbations naturelles causées par les insectes, ce qui pourrait affecter la dispersion par les organismes du sol et les plantes dans le nouveau paysage. Une portion du paysage déterminée en fonction d'espèces ayant besoin de plus d'espace pour maintenir leurs populations, incluant la nyctale boréale (Aegolius funereus), pourrait servir de guide pour établir la quantité requise de vieille forêt, et la taille appropriée des parcelles, dans un paysage en fonction du temps. Mots clés : forêts anciennes, biodiversité, richesse des espèces, gestion des forêts, sapin baumier. [Traduit par la rédaction] [ABSTRACT FROM AUTHOR]