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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 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 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.)

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]

Linear developments such as roads, seismic lines, and pipeline rights-of-way are common anthropogenic features in the boreal forest of Alberta. These features may act as barriers to the movement of threatened woodland caribou, Rangifer tarandus caribou. Seismic lines were not barriers to caribou movements, whereas roads with moderate vehicle traffic acted as semipermeable barriers to caribou movements. Twenty-two adult female and 1 adult male woodland caribou were captured and collared on February 17–19, 1998. Each caribou was fitted with a global positioning system collar. The greatest barrier effects were evident during late winter, when caribou crossed actual roads 6 times less frequently than simulated road networks. Semipermeable barrier effects may exacerbate functional habitat loss demonstrated through avoidance behavior. Caribou may cross roads less frequently than expected for a number of reasons, including an aversion to the physical barrier presented by a road and associated forest opening, vehicle traffic, or predation by humans. The effects of habitat fragmentation through habitat loss, avoidance, and the semipermeable barrier effects of roads should be considered in developing strategies to maintain woodland caribou populations in Alberta. Roads that act as semipermeable barriers to caribou movements may make the presence of caribou more predictable in space and time, and hence compromise the "spacing out" strategy that caribou adopt to reduce predation. The approach we have outlined in this paper is a useful method to quantify the effects of human developments acting as semipermeable barriers to animal movements and should be considered in the development of animal-movement models.