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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 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 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 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.)

The influence of site index on growth efficiency was studied for 411 dominant and codominant Abies balsamea (L.) Mill. and Picea rubens Sarg. from 10 sites across Maine, USA. Young A. balsamea (n = 204) were from stands precommercially thinned 15–20 years ago and ranged in site index from 18.4 to 24.3, while the older P. rubens (n = 207) were from stands that were not precommercially thinned and ranged in site index from 13.1 to 17.8. We hypothesized that site index positively influences growth efficiency. The results showed that volume increment – leaf area relationships and growth efficiency increased significantly with site index for A. balsamea but were unaffected by site index for P. rubens. A monotonic decreasing pattern of growth efficiency over increasing leaf area was found for both species. When standardized per unit site index, growth efficiency behaved nonlinearly for both species. L’influence de l’indice de qualité de station sur l’efficacité de croissance a été étudiée à partir de 411 Abies balsamea (L.) Mill. et Picea rubens Sarg. des étages dominants et codominants de 10 stations situées à travers l’État du Maine, aux tats-Unis. Les jeunes A. balsamea (n = 204) provenaient de peuplements ayant subi une éclaircie précommerciale 15 à 20 ans auparavant et dont l’indice de qualité de station variait de 18,4 à 24,3. De leur côté, les P. rubens (n = 207) provenaient de peuplements plus vieux n’ayant pas subi d’éclaircie précommerciale et dont l’indice de qualité de station variait de 13,1 à 17,8. Nous avons posé l’hypothèse que l’indice de qualité de station influence positivement l’efficacité de croissance. Les résultats indiquent que la relation entre l’accroissement en volume et la surface foliaire ainsi que l’efficacité de croissance augmentent significativement avec l’indice de qualité de station dans le cas d’A. balsamea, mais pas dans celui de P. rubens. Une décroissance monotone de l’efficacité de croissance en fonction de l’augmentation de la surface foliaire a été observée chez les deux espèces. Lorsqu’elle est standardisée par unité d’indice de qualité de station, l’efficacité de croissance se comporte de façon non linéaire chez les deux espèces. [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.)

Although headwater streams constitute a significant portion of stream length within watersheds, their aquatic fauna, contributions to regional biodiversity, and responses to forest management have been understudied. Macroinvertebrate communities, physical habitat, and water chemistry were sampled from 40 headwater streams in managed forests in the Oregon Coast Range mountains. We characterized functional and structural attributes of macroinvertebrate communities in relation to physical, chemical, and biological gradients. Substrate composition, specific conductance, and riparian forest age showed the strongest correlations with resultant ordination patterns in macroinvertebrate community composition. Among individual metrics of community structure and composition, total macroinvertebrate density and dominance by three taxa showed the strongest correlations with forest age. No community measures were related to densities of torrent salamanders (Rhyacotriton kezeri) or crayfish (Pacifastacus leniusculus), suggesting these potential predators had little influence on overall macroinvertebrate community structure. Rare taxa were sampled from several reaches, including Rhyacophila probably viquaea for which little information is available, and an Eobrachycentrus sp., previously known to occur only in the Cascade mountains. Headwater streams within these managed forests of northwestern Oregon appear to be taxa rich, continue to support taxa limited to headwater streams, and harbor taxa about which little is known. [ABSTRACT FROM AUTHOR]

Focuses on the use of direct gradient analysis and nearest-neighbor imputation to determine species composition and structure of forest vegetation in Oregon. Integration of vegetation measurements from regional grids of field plots; Factors considered in forest management; Changes in landscape patterns and forest conditions.

Old-growth forests are those that meet some threshold(s) determined by a scientific and political process. The main issue is what criteria to use to determine these thresholds; they must be practical enough to allow managers to delimit and manage old-growth stands in the field. People value forests with old and (or) big trees and primary forests that have a continuous heritage of natural disturbance and regeneration, even though the latter may include all stages of stand development and succession. We advocate uniting these two and using "primary forest", also called "natural heritage forest", as the criterion for delimiting old growth in regions where primary forest still exists. This criterion recognizes that the stage of development with big, old trees is part of a cycle of development, and it is necessary to have all the parts to continue to produce new examples of the older stages. The best available second-growth stands can be used in regions where primary forests are not available. Alternatively, threshold criteria for delimiting old growth can be based on tree size and age, but arbitrary criteria based on human size and age scales should be avoided in favour of criteria that specify stands dominated by trees relatively large and old for the species and site. Such criteria allow for old growth to occur across a variety of levels of site productivity, with trees of widely varying stature and with varying life-history characteristics, such as longevity, shade tolerance, and successional status. In any case, managers and scientists should work together to make sure that definitions work in the field but also include the ecological processes necessary to maintain the unique biological resources of old growth. The biological resources present in old growth may help to restore the second-growth landscape and allow reconstitution of forests in new places after global warming. Old-growth forests provide a baseline for comparison of effects of logging and natural disturbance, with respect to resilience to climatic change and disturbance, maintenance of species richness, and natural genetic structure of tree populations, which respond to different selective regimes in old growth and harvested forests. The species in old-growth remnants, their interactions and the resilience of the system after disturbance are as important or perhaps more so than the age and size of the trees at a given point in time. Key words: dwarf forest, Minnesota, old-growth processes, tree height.Les vieilles forêts sont celles qui rencontrent un ou des seuils déterminés par un processus scientifique ou politique. Le défi est de déterminer quels critères utiliser pour déterminer ces seuils; ils doivent être assez pratiques pour permettre aux aménagistes de délimiter et d'aménager les vieux peuplements sur le terrain. Le public valorise les forêts avec des arbres âgés ou de fortes dimensions, ainsi que les forêts primaires avec une histoire ininterrompue de perturbations naturelles et de régénérations. Nous proposons d'unir ces deux approches en utilisant le terme « forêt primaire » encore appelée « forêt patrimoniale naturelle », comme critère pour délimiter les vieilles forêts dans les régions où la forêt primaire existe toujours. Ce critère reconnaît que le stade de développement avec de gros arbres anciens constitue une partie du cycle de développement, et qu'il est nécessaire de disposer de toutes les parties du cycle pour continuer à produire de nouveaux exemples des stades les plus âgés. On peut utiliser les meilleures forêts de seconde venue, dans les régions où la forêt primaire n'existe plus. Comme alternative, les critères de seuil pour délimiter les vieilles forêts peuvent être basés sur la dimension et l'âge, mais les critères empiriques déterminés sur la base de dimension et d'âge à l'échelles humaines devraient être évités en faveurs de critères qui visent des peuplements dominés par des arbres relativement gros et âgés pour l'espèce et pour le site. De tels critères permettent de repérer des vieilles forêts pour un ensemble de niveaux de productivité des sites, avec des arbres de statures très variées, avec des caractéristiques variées de cycle de vie, tels que la longévité, la tolérance à l'ombre, et la place dans la succession. En toute éventualité, les aménagistes et les scientifiques devraient travailler ensemble pour s'assurer que les définitions sont utilisables sur le terrain, mais tiennent également compte du processus écologique nécessaire pour maintenir les ressources uniques de la vieille forêt. Les ressources biologiques présentes dans les vieilles forêts pourraient permettre de restaurer le paysage de seconde venue et de reconstituer des forêts en de nouveaux endroits, suite au réchauffement global. Les vieilles forêts fournissent une ligne de base pour comparer les effets à long terme de la récolte et des perturbations naturelles, en tenant compte de la résilience au changements de climat et de la perturbation, du maintient de la richesse en espèces, et de la richesse de la structure génétique des populations d'arbres, en réaction aux différents régimes sélectifs appliqués aux forêts âgées ou récoltées. Les espèces des vieilles forêts vestigiales, leurs interactions, et la résilience du système après perturbation sont aussi importantes, et peut-être plus importantes, que l'âge et la dimension des arbres, à un moment donné dans le temps. Mots clés : forêt naine, Minnesota, processus de vieillissement forestier, hauteur des arbres.[Traduit par la rédaction] [ABSTRACT FROM AUTHOR]